Upgrading and Repairing PCs Free Open Book

Upgrading and Repairing PCs

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Sixth-Generation (P6 Pentium Pro/II/III Class) Chipsets

Just as Intel clearly dominated the Pentium chipset world, it is also the leading vendor for chipsets supporting its P6 processor families. As discussed earlier, the biggest reason for this is that, since the Pentium first came out in 1993, Intel has been introducing new chipsets (and even complete ready-to-go motherboards) simultaneously with its new processors. This makes it hard for anybody else to catch up. Another problem for other chipset manufacturers is that they are required to license the CPU bus interface design before they can produce a matching chipset.

Note that because the Pentium Pro, Celeron, and Pentium II/III are essentially the same processor with different cache designs and minor internal revisions, the same chipset can be used for Socket 8 (Pentium Pro), Socket 370 (Celeron/Pentium III), and Slot 1 (Celeron/Pentium II/III) designs. Of course, the newer P6-class chipsets are optimized for the Socket 370 architecture and nobody is making any new designs for Socket 8 or Slot 1.

Table 4.12 shows the chipsets used on Pentium Pro motherboards.

Table 4.12. Pentium Pro Motherboard Chipsets (North Bridge)

Chipset

450KX

450GX

440FX

Code name

Orion

Orion Server

Natoma

Workstation date introduced

Nov. 1995

Nov. 1995

May 1996

Bus speed

66MHz

66MHz

66MHz

SMP (dual CPUs)

Yes

Yes (four CPUs)

Yes

Memory types

FPM

FPM

FPM/EDO/BEDO

Parity/ECC

Both

Both

Both

Maximum memory

8GB

1GB

1GB

L2 cache type

In CPU

In CPU

In CPU

Maximum cacheable

1GB

1GB

1GB

PCI support

2.0

2.0

2.1

AGP support

No

No

No

AGP speed

n/a

n/a

n/a

South Bridge

Various

Various

PIIX3

AGP = Accelerated graphics port

BEDO = Burst EDO

EDO = Extended data out

FPM = Fast page mode

Pburst = Pipeline burst (synchronous)

PCI = Peripheral component interconnect

PIIX = PCI ISA IDE Xcelerator

SDRAM = Synchronous dynamic RAM

SIO = System I/O

SMP = Symmetric multiprocessing (dual processors)

Note

PCI 2.1 supports concurrent PCI operations.

For the Celeron and Pentium II/III motherboards, Intel offers the chipsets in Table 4.13. 4xx series chipsets incorporate a North/South Bridge architecture, whereas 8xx series chipsets support the newer and faster hub architecture. P6/P7 (Pentium III/Celeron, Pentium 4, and Xeon) processor chipsets using hub architecture are shown in Table 4.14.

Table 4.13. P6 Processor Chipsets Using North/South Bridge Architecture

[1] The 440ZX is available in a cheaper 440ZX-66 version that runs only at 66MHz.

Table 4.14. P6 (Pentium III/Celeron) Processor Chipsets Using Hub Architecture

[2] The 810 chipsets have integral AGP 2x 3D video that is NOT upgradable via an external AGP adapter.

[3] The 815/815E chipsets have integral AGP 2x 3D video that IS upgradable via an APG 4x slot.

[4] The only difference between the 815 and 815E is in which I/O controller hub (South Bridge) is used.

Note

Pentium Pro, Celeron, and Pentium II/III CPUs have their secondary caches integrated into the CPU package. Therefore, cache characteristics for these machines are not dependent on the chipset but are quite dependent on the processor instead.

Most Intel chipsets are designed as a two-part system, using a North Bridge and a South Bridge component. Often the same South Bridge component can be used with several different North Bridge chipsets. Table 4.15 shows a list of all the Intel South Bridge components used with P6-class processors and their capabilities. The ICH2 is also used as part of some of the first seventh-generation (Pentium 4/Celeron 4) Intel chipsets.

Table 4.15. Intel South Bridge—I/O Controller Hub Chips for P6

Chip Name

SIO

PIIX

PIIX3

PIIX4

PIIX4E

ICH0

ICH

ICH2

Part number

82378IB/ZB

82371FB

82371SB

82371AB

82371EB

82801AB

82801AA

82801BA

IDE support

None

BMIDE

BMIDE

UDMA-33

UDMA-33

UDMA-33

UDMA-66

UDMA-100

USB support

None

None

1C/2P

1C/2P

1C/2P

1C/2P

1C/2P

2C/4P

CMOS/clock

No

No

No

Yes

Yes

Yes

Yes

Yes

ISA support

Yes

Yes

Yes

Yes

Yes

No

No

No

LPC support

No

No

No

No

No

Yes

Yes

Yes

Power management

SMM

SMM

SMM

SMM

SMM/ACPI

SMM/ACPI

SMM/ACPI

SMM/ACPI

SIO = System I/O

PIIX = PCI ISA IDE (ATA) Xcelerator

ICH = I/O controller hub

USB = Universal serial bus

1C/2P = 1 controller, 2 ports

2C/4P = 2 controllers, 4 ports

IDE = Integrated Drive Electronics (ATA = AT attachment)

BMIDE = Bus master IDE (ATA)

UDMA = Ultra-DMA IDE (ATA)

ISA = Industry standard architecture bus

LPC = Low pin count bus

SMM = System management mode

ACPI = Advanced configuration and power interface

The following sections examine the chipsets for P6 processors up through the Celeron and Pentium III.

Intel 450KX/GX (Orion Workstation/Server)

The first chipsets to support the Pentium Pro were the 450KX and GX, both code named Orion. The 450KX was designed for networked or standalone workstations; the more powerful 450GX was designed for fileservers. The GX server chipset was particularly suited to the server role because it supports up to four Pentium Pro processors for symmetric multiprocessing (SMP) servers, up to 8GB of four-way interleaved memory with ECC or parity, and two bridged PCI buses. The 450KX is the workstation or standalone user version of Orion and as such it supports fewer processors (one or two) and less memory (1GB) than the GX. The 450GX and 450KX both have full support for ECC memory—a requirement for server and workstation use.

The 450GX and 450KX North Bridge comprises four individual chip components—an 82454KX/GX PCI bridge, an 82452KX/GX data path (DP), an 82453KX/GX data controller (DC), and an 82451KX/GX memory interface controller (MIC). Options for QFP or BGA packaging were available on the PCI Bridge and the DP. BGA uses less space on a board.

The 450's high reliability is obtained through ECC from the Pentium Pro processor data bus to memory. Reliability is also enhanced by parity protection on the processor bus, control bus, and all PCI signals. In addition, single-bit error correction is provided, thereby avoiding server downtime because of spurious memory errors caused by cosmic rays.

Until the introduction of the following 440FX chipset, these were used almost exclusively in fileservers. After the debut of the 440FX, the expensive Orion chips all but disappeared due to their complexity and high cost.

Intel 440FX (Natoma)

The first popular mainstream P6 (Pentium Pro or Pentium II) motherboard chipset was the 440FX, which was code named Natoma. Intel designed the 440FX to be a lower-cost and somewhat higher-performance replacement for the 450KX workstation chipset. It offered better memory performance through support of EDO memory, which the prior 450KX lacked.

The 440FX uses half the number of components that the previous Intel chipset used. It offers additional features, such as support for the PCI 2.1 (concurrent PCI) standard, support for USB, and reliability through ECC.

The concurrent PCI processing architecture maximizes system performance with simultaneous activity on the CPU, PCI, and ISA buses. Concurrent PCI provides increased bandwidth to better support 2D/3D graphics, video and audio, and processing for host-based applications. ECC memory support delivers improved reliability to business system users.

The main features of this chipset include

  • Support for up to 1GB of EDO memory

  • Full 1GB cacheability (based on the processor because the L2 cache and tag are in the CPU)

  • Support for USB

  • Support for Bus master IDE

  • Support for full parity/ECC

The 440FX consists of a two-chip North Bridge. The main component is the 82441FX PCI Bridge and Memory controller, along with the 82442FX Data Bus accelerator for the PCI bus. This chipset uses the PIIX3 82371SB South Bridge chip that supports high-speed Bus Master DMA IDE interfaces and USB, and it acts as the bridge between the PCI and ISA buses.

Note that this was the first P6 chipset to support EDO memory, but it lacked support for the faster SDRAM. Also, the PIIX3 used with this chipset does not support the faster Ultra DMA IDE hard drives.

The 440FX was the chipset used on the first Pentium II motherboards, which have the same basic architecture as the Pentium Pro. The Pentium II was released several months before the chipset that was supposedly designed for it was ready, so early PII motherboards used the older 440FX chipset. This chipset was never designed with the Pentium II in mind, whereas the newer 440LX was optimized specifically to take advantage of the Pentium II architecture. For that reason, I normally recommended that people stay away from the original 440FX-based PII motherboards and wait for Pentium II systems that used the forthcoming 440LX chipset. When the new chipset was introduced, the 440FX was quickly superseded by the improved 440LX design.

Intel 440LX

The 440LX quickly took over in the marketplace after it debuted in August of 1997. This was the first chipset to really take full advantage of the Pentium II processor. Compared to the 440FX, the 440LX chipset offers several improvements:

  • Support for the new AGP video card bus

  • Support for 66MHz SDRAM memory

  • Support for the Ultra DMA IDE interface

  • Support for USB

The 440LX rapidly became the most popular chip for all new Pentium II systems from the end of 1997 through the beginning of 1998.

Intel 440EX

The 440EX was designed to be a low-cost, lower-performance alternative to the 440LX chipset. It was introduced in April 1998, along with the Intel Celeron processor. The 440EX lacks several features in the more powerful 440LX, including dual processor and ECC or parity memory support. This chipset is basically designed for low-end 66MHz bus-based systems that use the Celeron processor. Note that boards with the 440EX also fully support a Pentium II but lack some of the features of the more powerful 440LX or 440BX chipsets.

The main things to note about the 440EX are listed here:

  • Designed with a feature set tuned for the low-end PC market

  • Primarily for the Intel Celeron processor

  • Supports AGP

  • Does not support ECC or parity memory

  • Single processor support only

The 440EX consists of an 82443EX PCI AGP Controller (PAC) North Bridge component and the new 82371EB (PIIX4E) South Bridge chip.

Note

The original 266MHz and 300MHz Celeron processors used with the 440EX chipset provided very low performance because these processors lacked any onboard Level 2 cache memory. Starting with the 300MHz Celeron 300A, Celeron added 128KB of Level 2 cache to its SEP packaging; all Socket 370 Celerons also include Level 2 cache. You should consider upgrading to a faster Celeron CPU with Level 2 cache if your 440EX-based system uses one of the original Celeron processors.

Intel 440BX

The Intel 440BX chipset was introduced in April 1998 and was the first chipset to run the processor host bus (often called the front-side bus, or FSB) at 100MHz. The 440BX was designed specifically to support the faster Pentium II/III processors at 350MHz and higher. A mobile version of this chipset is the first Pentium II/III chipset for notebook or laptop systems.

The main change from the previous 440LX to the BX is that the 440BX chipset improves performance by increasing the bandwidth of the system bus from 66MHz to 100MHz. Because the chipset can run at either 66MHz or 100MHz, it allows one basic motherboard design to support all Pentium II/III processor speeds based on either the 66MHz or 100MHz processor bus.

Here are the Intel 440BX highlights:

  • Support for 100MHz SDRAM (PC100); the now-common PC133 RAM can also be installed, but it will still run at just 100MHz

  • Support for both 100MHz and 66MHz system and memory bus designs

  • Support for up to 1GB of memory in up to four banks (four DIMMs)

  • Support for ECC memory

  • Support for ACPI

  • The first chipset to support the Mobile Intel Pentium II processor

The Intel 440BX consists of a single North Bridge chip called the 82443BX Host Bridge/Controller, which is paired with a new 82371EB PCI-ISA/IDE Xcelerator (PIIX4E) South Bridge chip. The new South Bridge adds support for the ACPI specification version 1.0. Figure 4.29 shows a typical system block diagram using the 440BX.

Figure 4.29. System block diagram using the Intel 440BX chipset.

graphics/04fig29.gif

The 440BX was a popular chipset during 1998 and into 1999. It offered superior performance and high reliability through the use of ECC, SDRAM, and DIMMs.

Intel 440ZX and 440ZX-66

The 440ZX was designed to be a low-cost version of the 440BX. The 440ZX brings 66MHz or 100MHz performance to entry-level Celerons (with or without Level 2 cache) and low-end Pentium II/III systems. The 440ZX is pin compatible with the more expensive 440BX, meaning existing 440BX motherboards can be easily redesigned to use this lower-cost chipset.

Note that two versions of the 440ZX are available: The standard one runs at 100MHz or 66MHz, and the 440ZX-66 runs only at the slower 66MHz.

The features of the 440ZX include the following:

  • Support for Celeron and Pentium II/III processors at up to 100MHz bus speeds

  • These main differences from the 440BX:

    • No parity or ECC memory support

    • Only two banks of memory (two DIMMs) supported

    • Maximum memory only 256MB

The 440ZX is not a replacement for the 440BX; instead, it was designed to be used in less expensive systems (such as those based on the micro-ATX form factor), in which the greater memory capabilities, performance, and data integrity functions (ECC memory) of the 440BX are unnecessary.

Intel 440GX

The Intel 440GX AGP set is the first chipset optimized for high-volume midrange workstations and lower-cost servers. The 440GX is essentially a version of the 440BX that has been upgraded to support the Slot 2 (also called SC330) processor slot for the Pentium II/III Xeon processor. The 440GX can still be used in Slot 1 designs, as well. It also supports up to 2GB of memory, twice that of the 440BX. Other than these items, the 440GX is essentially the same as the 440BX. Because the 440GX is core compatible with the 440BX, motherboard manufacturers could quickly and easily modify their existing Slot 1 440BX board designs into Slot 1 or 2 440GX designs.

The main features of the 440GX include the following:

  • Support for Slot 1 and Slot 2

  • Support for 100MHz system bus

  • Support for up to 2GB of SDRAM memory

This chipset allows for lower-cost, high-performance workstations and servers using the Slot 2–based Xeon processors.

Intel 450NX

The 450NX chipset is designed for multiprocessor systems and standard high-volume servers based on the Pentium II/III Xeon processor. The Intel 450NX chipset consists of four components: the 82454NX PCI Expander Bridge (PXB), 82451NX Memory and I/O Bridge Controller (MIOC), 82452NX RAS/CAS Generator (RCG), and 82453NX Data Path Multiplexor (MUX).

The 450NX supports up to four Pentium II/III Xeon processors at 100MHz. Two dedicated PCI Expander Bridges can be connected via the Expander Bus. Each PXB provides two independent 32-bit, 33MHz PCI buses, with an option to link the two buses into a single 64-bit, 33MHz bus.

Figure 4.30 shows a typical high-end server block diagram using the 450NX chipset.

Figure 4.30. High-end server block diagram using the Intel 440NX chipset.

graphics/04fig30.jpg

The 450NX supports one or two memory cards. Each card incorporates an RCG chip and two MUX chips, in addition to the memory DIMMs. Up to 8GB of memory is supported in total.

The primary features of the 450NX include the following:

  • Slot 2 (SC330) processor bus interface at 100MHz

  • Support for up to four-way processing

  • Support for two dedicated PCI Expander Bridges

  • Up to four 32-bit PCI buses or two 64-bit PCI buses

The 450NX chipset does not support AGP because high-end video is not an issue in network fileservers.

Intel 810, 810E, and 810E2

Introduced in April 1999, the Intel 810 chipset (code named Whitney) represents a major change in chipset design from the standard North and South Bridges that have been used since the 486 days. The 810 chipset allows for improvements in system performance, all for less cost and system complexity. The 810 (which supports 66MHz and 100MHz processor buses) was later revised as the 810E with support for the 133MHz processor bus.

Note

The 810E2 uses the same 82810E GMCH as the 810E but pairs it with the 82801BA I/O Controller Hub (ICH2) used by the Intel 815E. For information about the 82801BA ICH2 chip, see the section "Intel 815 Family," later in this chapter.

The major features of the 810E chipset include

  • 66/100/133MHz system bus

  • Integrated AGP 2x Intel 3D graphics

  • Efficient use of system memory for graphics performance

  • Optional 4MB of dedicated display cache video memory

  • Digital Video Out port compatible with DVI specification for flat-panel displays

  • Software MPEG-2 DVD playback with hardware motion compensation

  • 266MBps hub interface

  • Support for ATA-66

  • Integrated Audio-Codec 97 (AC'97) controller

  • Support for low-power sleep modes

  • Random number generator (RNG)

  • Integrated USB controller

  • LPC bus for Super I/O and Firmware Hub (ROM BIOS) connection

  • Elimination of ISA bus

The 810E chipset consists of three major components (see Figure 4.31):

  • 82810E Graphics Memory Controller Hub (GMCH). 421 BGA package (the original 810 chipset used the 82810 GMCH).

  • 82801 Integrated Controller Hub (ICH). 241 BGA package.

  • 82802 Firmware Hub (FWH). In either 32-pin plastic leaded chip carrier (PLCC) or 40-pin thin small outline package (TSOP) packages. Although a functional part of the chipset, this component is actually sold separately by Intel to motherboard developers.

Figure 4.31. Intel 810E chipset showing the 82810E (GMCH), 82801 (ICH), and 82802 (FWH) chips. Photograph used by permission of Intel Corporation.

graphics/04fig31.jpg

Compared to the previous North/South Bridge designs, there are some fairly significant changes in the 810 chipset. The previous system designs had the North Bridge acting as the memory controller, talking to the South Bridge chip via the PCI bus. This new design has the GMCH taking the place of the North Bridge, which talks to the ICH via a 66MHz dedicated interface called the accelerated hub architecture (AHA) bus instead of the previously used PCI bus. In particular, implementing a direct connection between the North and South Bridges in this manner was key in implementing the new UDMA-66 high-speed IDE interface for hard disks, DVD drives, and other IDE devices.

Figure 4.32 shows a system block diagram for the 810E chipset. With the 810 chipset family, ISA is finally dead.

Figure 4.32. Intel 810E chipset system block diagram.

graphics/04fig32.jpg

The 82810E GMCH uses an internal Direct AGP (integrated AGP) interface to create 2D and 3D effects and images. The video capability integrated into the 82810E chip features hardware motion compensation to improve software DVD video quality; it also features both analog and direct digital video out ports, which enable connections to either traditional TVs (via an external converter module) or a direct digital flat panel display. The GMCH chip also incorporates the System Manageability Bus, which enables networking equipment to monitor the 810 chipset platform. Using ACPI specifications, the system manageability function enables low-power sleep mode and conserves energy when the system is idle.

The 82801 I/O Controller Hub employs AHA for a direct connection from the GMCH chip. This is twice as fast (266MBps) as the previous North/South Bridge connections that used the PCI bus, and it uses far fewer pins for reduced electrical noise. Plus, the AHA bus is dedicated, meaning that no other devices will be on it. The AHA bus also incorporates optimized arbitration rules allowing more functions to run concurrently, enabling better video and audio performance.

The ICH also integrates dual IDE controllers, which run up to either 33MBps (UDMA-33 or Ultra-ATA/33) or 66MBps (UDMA-66 or Ultra-ATA/66). Note that two versions of the ICH chip exist. The 82801AA (ICH) incorporates the 66MBps-capable ATA/IDE and supports up to six PCI slots, whereas the 82801AB (ICH0) supports only 33MBps ATA/IDE maximum and supports up to four PCI slots.

The ICH also integrates an interface to an Audio-Codec 97 (AC97) controller, dual USB ports, and the PCI bus with up to four or six slots. The Integrated Audio-Codec 97 controller enables software audio and modem by using the processor to run sound and modem software via very simple digital-to-analog conversion circuits. Reusing existing system resources lowers the system cost by eliminating components.

The 82802 Firmware Hub (FWH) incorporates the system BIOS and video BIOS, eliminating a redundant nonvolatile memory component. The BIOS within the FWH is flash-type memory, so it can be field-updated at any time. In addition, the 82802 contains a hardware RNG. The RNG provides truly random numbers to enable fundamental security building blocks supporting stronger encryption, digital signing, and security protocols. Two versions of the FWH are available, called the 82802AB and 82802ACy. The AB version incorporates 512KB (4Mb) of Flash BIOS memory, and the AC version incorporates a full 1MB (8Mb) of BIOS ROM.

With the Intel 810 and 810E chipsets, Intel did something that many in the industry were afraid of: It integrated the video and graphics controller directly into the motherboard chipset with no means of upgrade. This means systems using the 810 chipset don't have an AGP slot and aren't capable of using conventional AGP video cards. For the low-end market for which this chipset is designed, lacking an AGP slot shouldn't be too much of a drawback. Higher-end systems, on the other hand, use the 815 or other chipsets that do support AGP slots. Intel calls the integrated interface Direct AGP, and it describes the direct connection between the memory and processor controllers with the video controller all within the same chip.

This means the video card as we know it, will be reserved only for midrange and higher-end systems, as well as gaming-oriented systems. With the 810 as well as subsequent chipsets with integrated video, Intel has let it be known in a big way that it has entered the PC video business.

In fact, the theme with the 810 chipset is one of integration. The integrated video means no video cards are required; the integrated AC97 interface means that conventional modems and sound cards are not required. Plus, there is an integrated CMOS/Clock chip (in the ICH), and even the BIOS is integrated in the FWH chip. All in all, the 810 should be taken as a sign for things to come in the PC industry, which means more integration, better overall performance for low-end and mainstream systems, and less overall cost.

Intel Random Number Generator

The 8xx chipset series features the Intel Random Number Generator (RNG). The RNG is built in to the 82802 FWH, which is the ROM BIOS component used on 8xx-based motherboards. The RNG provides software with true nondeterministic random numbers.

Most security routines, especially those providing authentication or encryption services, require random numbers for purposes such as key code generation. One method of cracking these types of codes is to predict the random numbers being used to generate the keys. Current methods that use system and user input as a seed to a conventional pseudorandom number generator have proven vulnerable to this type of attack. The Intel RNG uses thermal noise across a resistor contained in the FWH (that is, ROM BIOS in 8xx-based boards) to generate true nondeterministic, unpredictable random numbers. Therefore, "random" numbers generated by 8xx-series chipsets really are random.

Intel 815 Family

Introduced in June 2000, the 815 and 815E chipsets are mainstream PC chipsets with integral video that is also upgradable via an AGP 4x slot. An 815EP version introduced a few months later lacks the integrated video for lower cost. In March 2001, the 815P chipset, an improved version of the 815EP, was introduced. In September 2001, the last members of the family—the 815G and 815EG—were introduced. Note that the G indicates that these chipsets also include integrated video.

The 815 chipsets are designed for Slot-1 or Socket-370 processors, such as the Celeron or Pentium III. These are the first chipsets from Intel designed to directly support PC133 SDRAM memory, allowing for a more affordable solution than other chipsets using RDRAM memory. Similar to the other 8xx series chipsets from Intel, the 815 uses hub architecture that provides a 266MBps connection between the main chipset components and does not share the PCI bus like the prior North/South Bridge designs.

Although six variations on the 815 chipset are available, only five different parts are used to create the various members of the family: one memory controller hub (82815EP MCH: North Bridge replacement without integrated graphics), two graphics memory controller hubs (82815 or 82815G GMCH: North Bridge replacement with integrated graphics), and two I/O controller hubs (ICH and ICH2). Table 4.16 shows how these parts are combined to create the various members of the family.

Table 4.16. 815 Chipset Family Components

Chipset Name

82815 GMCH

82815G GMCH

82815EP MCH

82801AA ICH

82801BA ICH2

815

*

  

*

 

815E

*

   

*

815EP

  

*

 

*

815P

  

*

*

 

815G

 

*

 

*

 

815EG

 

*

  

*

Figure 4.33 illustrates one member of this chipset family, the 815E.

Figure 4.33. Intel 815E chipset showing the 82815 (GMCH) and 82801BA (ICH2) chips. Photograph used by permission of Intel Corporation.

graphics/04fig33.gif

All 815 chipsets support the following features:

  • 66/100/133MHz system bus

  • 266MBps hub interface

  • ATA-100 (815E/EP/EG) or ATA-66 (815/P/G)

  • PC100 or PC133 CL-2 SDRAM (also PC66 with 815G/GE)

  • Up to 512MB RAM

  • Integrated Audio-Codec 97 (AC97) controller

  • Low-power sleep modes

  • RNG for stronger security products

  • One (815/P/G) or two (815E/EP/EG) integrated USB controllers with either two or four ports, respectively

  • LPC bus for Super I/O and Firmware Hub (ROM BIOS) connection

  • Elimination of ISA Bus

The 815/E/G/EG also support the following:

  • Integrated Intel AGP 2x 3D graphics

  • Efficient use of system memory for graphics performance

  • Optional 4MB of dedicated display cache video memory

  • Digital Video Out port compatible with DVI specification for flat panel displays

  • Software MPEG-2 DVD playback with hardware motion compensation

The 815E/EP/EG uses the ICH2, which is most notable for providing ATA-100 support, allowing 100MBps drive performance. Of course, few drives can really take advantage of this much throughput, but in any case, there won't be a bottleneck there. The other notable feature is having two USB 1.1 controllers and four ports on board. This allows double the USB performance by splitting up devices over the two ports and can allow up to four connections before a hub is required.

Integrated Ethernet

Another important feature of the 815 series is the integration of a fast Ethernet controller directly into the chipset. The integrated LAN controller works with one of three new physical layer components from Intel and enables three distinct solutions for computer manufacturers. These include

  • Enhanced 10/100Mbps Ethernet with Alert on LAN technology

  • Basic 10/100Mbps Ethernet

  • 1Mbps home networking

These physical layer components can be placed directly on the PC motherboard (additional chips) or installed via an adapter that plugs into the CNR slot. The CNR slot and cards enable PC assemblers to build network-ready systems for several markets.

AGP Inline Memory Module

Although the 815/815E feature is essentially the same built-in AGP 2x 3D video that comes with the 810 chipset, the difference is upgradeability. The video can easily be upgraded by adding a graphics performance accelerator (GPA) card (see Figure 4.34) or an AGP 4x card for maximum 3D graphics and video performance. The GPA card (also called the AGP Inline Memory Module, or AIMM) is essentially a high-performance video memory card that works in the AGP 4x slot and improves the performance of the integrated video by up to 30%. Unfortunately, these are not commonly sold and are somewhat expensive. For even more performance, you can install a full 4x AGP card in the AGP 4x slot, which disables the integrated video. By having the video integrated, very low-cost systems with reasonable video performance can be assembled. By later installing either the GPA or a full 4x AGP card, you can improve video performance up to 100% or more.

Figure 4.34. A typical 4MB GPA/AIMM module, which attaches to the AGP slot of a motherboard using the 815 or 815E chipset.

graphics/04fig34.gif

PC133 Memory Support

Another important feature of the 815 chipset is the support of PC133 memory. The 815 family also uses PC100 memory. With PC133 support, Intel has also officially set a standard for PC133 memory that was higher than some of the PC133 memory on the market at the time of introduction. To meet the Intel PC133 specification, the memory must support what is called 2-2-2 timing, sometimes also known as CAS-2 (column address strobe) or CL-2 timing. The numbers refer to the number of clock cycles for the following functions to complete:

  • Precharge command to Active command. Charges the memory's storage capacitors to prepare them for data

  • Active command to Read command. Selects rows and columns in memory array for reading

  • Read command to Data Out. Reads data from selected rows and columns for transmission

Some of the PC133 memory on the market takes three cycles for each of these functions and would therefore be termed PC133 3-3-3, CAS-3, or CL-3 memory. Note that the faster PC133 CL-2 can be used in place of the slower CL-3 variety, but not the other way around.

As a result of the tighter cycling timing, PC133 CL-2 offers a lead-off latency of only 30ns, instead of the 45ns required by PC133 CL-3. This results in a 34% improvement in initial access due to the decreased latency.

The 815 chipset was a popular chipset for the mainstream PC market that didn't want to pay the higher prices for RDRAM memory. The 815 was essentially designed to replace the venerable 440BX chipset.

Intel 820 and 820E

The Intel 820 chipsets use the hub-based architecture like all the 800 series chips and are designed to support slot 1 or socket 370 processors, such as the Pentium III and Celeron (see Figure 4.35). The 820 chipset supports RDRAM memory technology, 133MHz system bus, and 4x AGP.

Figure 4.35. Intel 820 chipset showing the 82820 (MCH), 82801 (ICH), and 82802 (FWH) chips. Photograph used by permission of Intel Corporation.

graphics/04fig35.jpg

The 82820 MCH provides the processor, memory, and AGP interfaces. Two versions are available: One supports a single processor (82820), whereas the other supports two processors (82820DP). Either is designed to work with the same 82801 ICH as used with the other 800 series chipsets, such as the 810 and 840. The 820 chipset also uses the 82802 FWH for BIOS storage and for the Intel RNG.

The connection between the MCH and ICH uses what is called the Intel Hub Architecture bus instead of the PCI bus as with prior North/South Bridge chipsets. The hub architecture bus provides twice the bandwidth of PCI at 266MB per second, enabling twice as much data to flow between them. The hub architecture bus also has optimized arbitration rules, allowing more functions to run concurrently, as well as far fewer signal pins, reducing the likelihood of encountering or generating noise and signal errors.

The 820 chipset is designed to use RDRAM memory, which has a maximum throughput of up to 1.6GBps. The 820 supports PC600, PC700, and PC800 RDRAM, delivering up to 1.6GBps of theoretical memory bandwidth in the PC800 version. PC800 RDRAM is a 400MHz bus running double-clocked and transferring 16 bits (2 bytes) at a time (2x400MHzx2 bytes = 1.6GBps). Two RIMM sockets are available to support up to 1GB of total system memory.

The AGP interface in the 820 enables graphics controllers to access main memory at AGP 4x speed, which is about 1GB per second—twice that of previous AGP 2x platforms. Figure 4.36 shows the 820 chipset architecture. Because the 820 was designed for mid-range to higher-end systems, it does not include integrated graphics, relying instead on the AGP 4x slot to contain a graphics card.

Figure 4.36. Intel 820 chipset architecture.

graphics/04fig36.gif

820 Chipset features include

  • 100/133MHz processor bus

  • Intel 266MBps hub interface

  • PC800 RDRAM RIMM memory support

  • AGP 4x support

  • ATA-100 (820E) or ATA-66 interface

  • Intel RNG

  • LPC interface

  • AC97 controller

  • One (820) or two (820E) USB buses with either two or four ports, respectively

The 820 chipset consists of three main components with a few optional extras. The main component is the 82820 (single-processor) or 82820DP (dual-processor) MCH, which is a 324 BGA chip. That is paired with an 82801 ICH, which is a 241 BGA chip, and finally it has the 82802 FWH, which is really just a fancy Flash ROM BIOS chip. Optionally, there can be an 82380AB PCI-ISA bridge that is used only if the board is equipped with ISA slots.

The newer 820E version uses an updated 82801BA ICH2, which supports ATA-100 and incorporates dual USB controllers with two ports each, for a total of four USB ports.

820 Chipset MTH Bug

The 820 chipset is designed to support RDRAM memory directly. However, because the market still demanded lower-cost SDRAM, Intel created an RDRAM-to-SDRAM translator chip called the Memory Translator Hub (MTH). This enabled them to produce 820 chipset motherboards that supported SDRAM instead of the more expensive RDRAM.

Because the design of the MTH was proven defective, the chip (and any board using it) was simply discontinued. On May 10, 2000, Intel officially announced that it would replace any motherboards using the MTH with a new board lacking the component. The MTH translates signals from SDRAM memory to the Intel 820 chipset and is used only with motherboards utilizing SDRAM and the Intel 820 chipset; boards using RDRAM don't have an MTH and were not affected. Intel found electrical noise issues with the MTH that can cause some systems to intermittently reset, reboot, or hang. In addition, the noise issue can, under extreme conditions, potentially cause data corruption.

The MTH bug forced Intel to recall and replace more than a million motherboards in mid-2000, with new versions lacking the MTH and thus supporting only RDRAM memory. The final bill for this recall was reported at about $253 million, making it perhaps the most costly recall of computer components since the infamous Pentium math bug in 1994. I found it interesting that, due to the fact that Intel did more than $24.4 billion in sales the previous year, at least one article classified the cost of this recall as "chump change" to the chip giant!

Intel has an MTH I.D. Utility at www.intel.com/support/mth that will tell you whether you have that component and whether your board is eligible for replacement, including a 128MB RDRAM RIMM. Again, note that the 820 chipset was really designed to support RDRAM as the native type of memory, and RDRAM-based systems are not affected because they don't use the memory translator hub component.

Intel 840

The Intel 840 is a high-end chipset designed for use in high-performance multiprocessor systems using slot 1, slot 2 (Xeon processor), or Socket 370 processors. The 840 chipset uses the same hub architecture and modular design as the rest of the 800 family chipsets, with some additional components enabling more performance. See Figure 4.37 for a photo of the Intel 840 chipset.

Figure 4.37. Intel 840 chipset showing the 82840 (MCH), 82801 (ICH), 82802 (FWH), 82803 (MRH-R), 82804 (MRH-S), and 82806 (P64H) chips. Photograph used by permission of Intel Corporation.

graphics/04fig37.gif

As with the other 800 series chipsets, the 840 has three main components:

  • 82840 Memory Controller Hub. Provides graphics support for AGP 2x/4x, dual RDRAM memory channels, and multiple PCI bus segments for high-performance I/O.

  • 82801 I/O Controller Hub. Equivalent to the South Bridge in older chipset designs, except it connects directly to the MCH component via the high-speed Intel Hub Architecture bus. The ICH supports 32-bit PCI, IDE controllers, and dual USB ports.

  • 82802 Firmware Hub. Basically an enhanced Flash ROM chip that stores system BIOS and video BIOS, as well as an Intel RNG. The RNG provides truly random numbers to enable stronger encryption, digital signing, and security protocols.

In addition to the core components, parts are available for scaling up to a more powerful design. Three additional components can be added:

  • 82806 64-bit PCI Controller Hub (P64H). Supports 64-bit PCI slots at speeds of either 33MHz or 66MHz. The P64H connects directly to the MCH using Intel Hub Architecture, providing a dedicated path for high-performance I/O. This is the first implementation of the 66MHz 66-bit PCI on a PC motherboard chipset, allowing for a PCI bus four times faster than the standard 32-bit 33MHz version.

  • 82803 RDRAM-based Memory Repeater Hub (MRH-R). Converts each memory channel into two memory channels for expanded memory capacity.

  • 82804 SDRAM-based Memory Repeater Hub (MRH-S). Translates the RDRAM protocol into SDRAM-based signals for system memory flexibility. This would be used only in 840 systems that supported SDRAM.

Figure 4.38 shows the 840 chipset architecture.

Figure 4.38. Intel 840 chipset architecture.

graphics/04fig38.jpg

840 chipset features include

  • 100/133MHz processor bus

  • Dual RDRAM memory channels, operating simultaneously and providing up to 3.2GBps memory bandwidth

  • 16-bit wide implementation of Intel Hub Architecture (HI16), which enables high-performance concurrent PCI I/O with the optional P64H component

  • AGP 4x

  • Prefetch cache, unique to the 840 chipset, which enables highly efficient data flow and helps maximize system concurrency

  • Intel RNG (see the section "Intel Random Number Generator," earlier in this chapter)

  • USB support

Optionally, network interface and RAID controller interface chips can be added as well.

Third-Party (Non-Intel) P6-Class Chipsets

Several companies produce chipsets designed to support P6-class processors, including ALi Corporation (formerly known as Acer Laboratories), VIA Technologies, and SiS. The following sections discuss the offerings from these companies.

ALi Chipsets for P6-Class Processors

ALi has a variety of chipsets for the P6-class processors. Table 4.17 provides an overview of these chipsets.

Table 4.17. ALi Chipsets for Pentium Pro-II-III-Celeron

Chipset

Aladdin Pro II

Aladdin Pro 4

Aladdin TNT2

Aladdin Pro 5

Date introduced

1999

2000

1999

2000, 2001(T)

Part number

M1621

M1641/M1641B

M1631

M1651, M1651T

Bus speed

60, 66, 100MHz

100, 133, 200, 266MHZ (B)

66, 100, 133MHz

66, 100, 133, 200, 266MHz

Supported processors

Pentium II, Pentium Pro

Pentium II, III, Celeron

Pentium II, III, Celeron

Pentium II, III, Celeron (T version supports Tualatin)

Form factor

Slot 1, Socket 370

Slot 1, Socket 370

Slot 1, Socket 370

Slot 1, Socket 370

SMP (dual CPUs)

Yes

No

No

No

Memory types

FPM, EDO, PC100

PC100, PC133, DDR200, DDR266 (B)

PC66, 100, 133, EDO

PC66, PC100, PC133, DDR200, DDR266

Parity/ECC

ECC

ECC

ECC

Neither

Maximum memory

1GB (SDRAM), 2GB (EDO)

1.5GB

1.5GB

3GB

PCI support

2.2

2.2

2.2

2.2

PCI speed/width

33MHz/32-bit

33MHz/32-bit

33MHz/32-bit

33MHz/32-bit

AGP slot

1x/2x

1x/2x/4x

No

1x/2x/4x

Integrated video

No

No

Yes—TnT2

No

South Bridge

M1533 or M1543

M1535D

M1543C

M1535D

Table 4.18 provides an overview of the features of the South Bridge chips used in these chipsets.

Table 4.18. ALi South Bridge Chips Used with P6-Class Chipsets

South Bridge Chip

Number of USB Ports

ATA Support

Integrated Sound

Integrated Super I/O

M1533

2

ATA-33

No

No

M1543

2

ATA-33

No

Yes

M1535D

4

ATA-66

Yes[1]

Yes

M1535D+

6[2]

ATA-100

Yes[3]

Yes

M1543C

3

ATA-66

No

Yes

[1] SoundBlaster 16 compatible with wavetable

[2] Supports Legacy USB (mouse/keyboard)

[3] 3D PCI audio with Direct3D (DirectX) support, MIDI, SPDIF, SoundBlaster compatibility

For more information about these chipsets, see Upgrading and Repairing PCs, 14th Edition, found in electronic form on the DVD packaged with this book.

VIA Technologies Chipsets for P6-Class Processors

VIA Technologies has a variety of chipsets for the P6 processors. They are discussed in the following sections and Table 4.19.

Apollo Pro

The Apollo Pro is a high-performance chipset for Slot 1 mobile and desktop PC systems; it can also support the Socket 8 Pentium Pro processor. The Apollo Pro includes support for advanced system power management capability for both desktop and mobile PC applications, PC100 SDRAM, AGP 2x mode, and multiple CPU/DRAM timing configurations. The Apollo Pro chipset is comparable in features to the 440BX and PIIX4e chipsets from Intel and represents one of the first non-Intel chipsets to support the Socket 1 architecture.

The VIA Apollo Pro consists of two devices—the VT82C691 North Bridge chip and the VT82C596, a BGA-packaged South Bridge with a full set of mobile, power-management features. For cost-effective desktop designs, the VT82C691 can also be configured with the VT82C586B South Bridge.

The VT82C691 Apollo Pro North Bridge supports all Slot 1 (Intel Pentium II) and Socket 8 (Intel Pentium Pro) processors. The Apollo Pro also supports the 66MHz external bus speed and the newer 100MHz CPU external bus speed required by the 350MHz and faster Pentium II processors. AGP v1.0 and PCI 2.1 are also supported, as are FPM, EDO, and SDRAM. Various DRAM types can be used in mixed combinations in up to eight banks and up to 1GB of DRAM. EDO memory timing is 5-2-2-2-2-2-2-2 for back-to-back accesses, and SDRAM timing is 6-1-1-1-2-1-1-1 for back-to-back accesses.

The VT82C596 South Bridge supports both ACPI and APM and includes an integrated USB controller and dual Ultra DMA-66 EIDE ports.

Apollo Pro Plus

The VIA Apollo Pro Plus is a high-performance chipset for Slot 1/Socket 370 mobile and desktop PC systems.

Features include the following:

  • 66/100MHz CPU bus

  • AGP 1x

  • PCI 2.1 compliant

  • Support for eight banks up to 1GB PC-100 SDRAM

  • Support for both ACPI and legacy (APM) power management

  • Integrated USB controller

  • Ultra DMA-33 controller

The Apollo Pro consists of two chips: a VT82C693 North Bridge paired with either the VT82C596A mobile South Bridge or the VT82C686A Super South Bridge.

Table 4.19. VIA Technologies Chipsets for Pentium Pro-II-III-Celeron

Chipset

Apollo Pro

Apollo Pro Plus

Apollo KLE133 (PM601)

ProSavage PM133

Apollo Pro133

Apollo Pro133A

Apollo Pro PL133T

Apollo Pro 266/266T

Part number

VT82C691

VT82C693

VT8601

VT8605

VT82C693A

VT82694X

VT8605

VT8653

Bus speed

66, 100MHz

66, 100MHz

66, 100, 133MHz

66, 100, 133MHz

66, 100, 133MHz

66, 100, 133MHz

66, 100, 133MHz

66, 100, 133MHz

Supported processors

Pentium Pro, Pentium II, Celeron

Pentium II, Celeron

Pentium II, III, Celeron, VIA C3

Pentium II, III, Celeron, VIA C3

Pentium II, III, Celeron, VIA C3

Pentium II, III, Celeron, VIA C3

Pentium II, III Celeron (Tualatin), VIA C3

Pentium III, Celeron (Tualatin), VIA C3

Form factor

Socket 8, Slot 1

Slot 1, Socket 370

Slot 1, Socket 370

Slot 1, Socket 370

Slot 1, Socket 370

Slot 1, Socket 370

Slot 1, Socket 370

Socket 370

SMP (dual CPUs)

No

No

No

No

No

Yes

No

No

Memory types

FP, EDO, PC66, 100 SDRAM

FP, EDO, PC66, 100 SDRAM

PC66, 100, 133 SDRAM

PC66, 100, 133 SDRAM

PC66, 100, 133 SDRAM

PC66, 100, 133 SDRAM, EDO

PC100, 133 SDRAM

PC100, 133 SDRAM, DDR200, 266

Parity/ECC

No

No

No

No

No

Yes

No

No

Maximum memory

1GB

1GB

1GB

1.5GB

1.5GB

4GB

1.5GB

4GB

PCI support

2.1

2.1

2.1

2.2

2.1

2.2

2.2

2.2

PCI speed/width

33MHz/32-bit

33MHz/32-bit

33MHz/32-bit

33MHz/32-bit

33MHz/32-bit

33MHz/32-bit

33MHz/32-bit

33MHz/32-bit

AGP slot

1x, 2x

1x, 2x

1x, 2x

2x, 4x

1x, 2x

2x, 4x

2x, 4x

2x, 4x

Integrated video

No

No

Yes[1]

Yes

No

No

Yes[2]

No

South Bridge

VT82C596 or VT82C586B

VT82C596A

VT82C686A

VT8231

VT82C596B or VT82C586A

VT82C686A

VT8231

VT8233C[3]

[1] Trident Blade3D

[2] S3 Savage 4 (3D) integrating Savage 2000 (2D)

[3] Supports VIA 4x V-Link 266MHz high-speed interconnect between North Bridge and South Bridge

Table 4.20 provides an overview of the features of the South Bridge chips used in these chipsets.

Table 4.20. VIA South Bridge Chips Used with P6-Class Chipsets

South Bridge Chip

Number of USB Ports

ATA Support

Integrated Sound

Integrated Super I/O

Integrated 10/100 Ethernet

Supports V-Link

VT82C596

2

ATA-33

No

No

No

No

VT82C596A

2

ATA-33

No

No

No

No

VT82C686A

4

ATA-66

AC'97

Yes

No

No

VT82C586B

2

ATA-33

No

No

No

No

VT8231

4

ATA-100

AC'97

Yes

No

No

VT82C596B

4

ATA-66

AC'97

Yes

No

No

VT82C586A

No

ATA-33

No

No

No

No

VT8233(C)

6

ATA-100

AC'97

Yes

Yes[*]

Yes

[*] 3Com 10/100 Ethernet on C version only

Apollo Pro133

The VIA Apollo Pro133 was the first chipset on the market designed to support PC-133 SDRAM memory. This chipset supports Slot 1 and Socket 370 processors, such as the Intel Pentium III, Intel Celeron, and VIA Cyrix III processors.

Key features include the following:

  • Support for AGP 2x graphics bus

  • Support for 133/100/66MHz processor bus

  • PC-133 SDRAM memory interface

  • Support for 1.5GB of RAM

  • ATA-66 interface

  • Support for four USB ports

  • AC97 link for audio and modem

  • Hardware monitoring

  • Power management

The VIA Apollo Pro133 is a two-chip set consisting of the VT82C693A North Bridge controller and a choice of VT82C596B or VT82C686A South Bridge controllers.

Apollo KLE133

The VIA Apollo KLE133 (previously known as the PM601) chipset is a highly integrated chipset platform designed for the value PC and Internet appliance market. As such, this chipset has a built-in Trident Blade3D graphics engine and 10/100 Ethernet. The KLE133 is designed for Slot 1 and Socket 370 processors, such as the Pentium III, Celeron, and VIA C3.

Key features include the following:

  • Support for AGP 2x

  • Integrated Trident Blade3D AGP graphics engine

  • 66/100/133MHz processor bus

  • Support for PC-133 SDRAM memory

  • Integrated 10/100 Ethernet

  • Support for AC97 audio, MC'97 modem, Super I/O, and hardware monitoring

  • Four USB ports

  • Support for ATA-66

  • Advanced power management

The VIA Apollo KLE133 is a two-chip set consisting of the VT8601 North Bridge controller and the VT82C686A South Bridge controller.

Apollo Pro133A

The VIA Apollo Pro133A chipset is a North/South Bridge chipset designed to support Slot 1 and Socket 370 processors such as the Intel Pentium III, Intel Celeron, and VIA Cyrix III. The Apollo Pro133A is based on the previous Pro133 with even more high-end features added.

Features of the Apollo Pro133A include

  • AGP 4x graphics bus support

  • Support for one or two processors

  • 133/100/66MHz processor bus support

  • PC-133 SDRAM memory interface

  • ATA-66 interface

  • Support for four USB ports

  • AC97 link for audio and modem

  • Hardware monitoring

  • Power management

The VIA Apollo Pro133A chipset is a two-chip set consisting of the VT82C694X North Bridge controller and a choice of a VT82C596B or VT82C686A South Bridge controller.

ProSavage PM133

The VIA ProSavage PM133 integrates S3 Graphics' S3 Savage 4 and S3 Savage 2000 3D and 2D graphics engines with the Apollo Pro 133A chipset. The major features of the chipset are the same as for the Apollo Pro 133A, with the following additions:

  • 2MB–32MB shared memory architecture integrated with Savage 4 3D and Savage 2000 2D video

  • Z-buffering, 32-bit true-color rendering, massive 2K-by-2K textures, single-pass multiple textures, sprite antialiasing, and other 3D features

  • Support for DVD playback, DVI LCD displays, and TV-out

  • PCI 2.2 compliance

An optional AGP 4x interface allows the integrated AGP 4x video to be upgraded with an add-on card if desired. This two-chip set consists of the VT8605 North Bridge and VT8231 South Bridge.

The VT8231 South Bridge integrates the Super I/O and supports the LPC interface.

Apollo Pro266

The VIA Apollo Pro266 is a high-performance North/South Bridge chipset designed to support Socket 370 processors, including the Pentium III, Celeron, and VIA's own C3. The Apollo Pro 266 is the first chipset from VIA to replace the traditional PCI (133MBps) connection between North and South Bridge chips with VIA's 4x V-Link interconnect, which runs at 266MBps.

Features of the Apollo Pro266 include

  • AGP 2x/4x graphics bus support

  • 133/100/66MHz processor bus support

  • PC-100/133 SDRAM and PC200/266 DDR SDRAM memory interface

  • ATA-100 IDE interface

  • Support for six USB ports

  • Integrated AC97 six-channel audio

  • Integrated MC'97 modem

  • Integrated 10/100BASE-T Ethernet and 1/10MHz Home PNA networking

  • Hardware monitoring

  • ACPI/On Now! Power management

  • VIA 4x V-Link North/South Bridge interconnect'

The VIA Apollo Pro266 chipset is a two-chip set consisting of the 552-pin BGA VT8633 North Bridge controller and the 376-pin BGA VT8233 South Bridge controller. Figure 4.39 shows the architecture of the Apollo Pro266 chipset.

Figure 4.39. Apollo Pro266 chipset architecture.

graphics/04fig39.gif

Because of the V-Link high-speed interconnect between the North Bridge and South Bridge, PCI is managed by the South Bridge. This is similar to the way in which Intel hub architecture works, and this basic architecture has been followed by all subsequent VIA chipsets that use V-Link architecture.

Silicon Integrated Systems Chipsets for P6-Class Processors

Silicon Integrated Systems has a variety of chipsets for the P6-class processors. They are discussed in the following sections, and Table 4.21 provides a summary of them.

Table 4.21. Current SiS Chipsets for Pentium II/III/Celeron

Chipset

SiS620

SiS630

SiS630E

SiS630ET

SiS630S

SiS630ST

Bus speed