"AMD was kind enough to lock the multiplier on their latest series of processors, but leave an easy backdoor for those interested in overclocking. Rumor has it that AMD has removed the pins that control the multiplier on some CPUs, but as of this date, I have yet to see one. If you have one, send me some pics (not fake ones *cough*, not that anyone would do that), I'm sure the rest of the world would love to see it.
The trick to unlocking the CPU's multiplier is the L1 bridges. When the L1 contacts are open, the CPU dictates the multiplier, when connected (or closed, actually), the motherboard can adjust the multiplier. So, take out your CPU, and look closely at the substrate. You'll see this (unless your vendor put a damn Warranty Void if Removed sticker over them."