PC Hacks 100 Industrial-Strength Tips and Tools

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Hack 28 Unlock Your CPU Multiplier

Overclocked AMD processors benefit from this down-and-dirty hardware hack that allows you to change the CPU multiplier value.

The objective of this hack is to release the electronic "lock" that prevents you from changing an AMD CPU's clock multiplier value. This is done by connecting circuits on the top of the CPU chip itself. From the steps below, which identify whether or not the two circuits of interest are connected, you will know if your multiplier needs to be unlocked. Unlocking the multiplier involves some very serious, precision work on the CPU chip itself and is not for the faint-hearted, caffeine-addicted, easily excitable types. In other words, patience, steady hands, good eyes, and controlled breathing are desirable assets. This technique is also described for many (but not all) AMD Athlon CPUs at various hacking/overclocking and gaming enthusiasts' web sites like http://www.tomshardware.com, http://www.sysopt.com, and http://www.tweaktown.com.

You will need the following tools to execute this hack:

• An antistatic work mat or foam pad

• An antistatic wrist strap and grounding point

• A magnifying lens

• A #2 pencil or 0.5 mm mechanical pencil with HB2 lead

• Optionally, an automotive window defogger repair kit (silver paint)

• Optionally, a soldering iron with a miniature tip, and solder (I recommend eutectic or SN63/37 blend solder for better connections)

• Optionally, the XP Unlocking Kit from http://www.highspeedpc.com

You'll be working with the CPU removed from its socket, connection pins down, preferably sitting in antistatic foam or on an anti-static work surface. It's a good idea to wear an antistatic wrist strap, with the other end clipped to a safety/earth ground someplace nearby. Do not trust the chassis of your CPU to be grounded, because if you followed the advice from [Hack #2], the power cord will be disconnected and the chassis will have no connection to ground.

You can observe the area of the CPU we'll be working on, as shown in Figure 3-24, with the naked eye, but you will probably want to do the actual work looking through a magnifying glass. The points of contact you will be working on are about 0.5mm apart. (If you're not into the metric system, let's just say it's a really, really small distance!) For visual comparison, the pencil in the photograph is an average mechanical pencil with 0.5 mm lead.

Figure 3-24. AMD L1 multiplier selection pins

Locate the group of gold-colored connection points, known as pads, labeled "L1" on top of the CPU body—that's where you're headed. Orient the chip so "L1" appears normal—left-to-right, right-side up facing you. There will be four or five sets of connection pads, most of them connected up-and-down. If all of the pads are connected—appearing as four or five vertical bars—the CPU's multiplier section is already unlocked, as is the case with the CPU shown in Figure 3-24, which came that way from AMD. If there are gaps between opposing pads top-to-bottom (like the two sets of dots in the middle two columns to the right of "L3" or "L4"), those are connections at "L1" that will have to be closed up. There should be no horizontal interconnections between the distinct vertical bars or across the dots left-to-right.

The first three items on the list of tools above are for your safety, comfort, and convenience, as well as the safety of the CPU. The remaining four items are choices for methods to "connect the dots"—drawing a small pencil line or placing a miniscule blob of silver paint or solder across the dots.

For experimentation, to see if this overclocking technique will work, start by using the pencil to connect the dots. The graphite of the pencil lead is suitably conductive to make a good temporary signal connection between the dots. Replace the CPU, heat sink, and fan; start up the system; and see if your overclock settings work OK. If the hack doesn't work, you can erase it, literally, by rubbing the lead off with a standard pencil eraser. If this modification works and you like it, you can erase the temporary connection, clean the area, and then solder or paint (using the silver repair paint) a more permanent connection blob in place.

Connect the dots to form a vertical bar. Connecting adjacent side-to-side dots or bridges can damage the CPU.

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