In an interesting thread over at xtremesystems.org, a forum user posted several screenshots of an AMD Magny Cours 12-core CPU overclocked to 3.2GHz.

It might not be something you're likely see in your desktop anytime soon, but the performance is pure pornography. The CPU was pushed to 3.3GHz, but it wasn't stable in all tests. Believe it or not, the OC was done using an Opteron stock cooler.

CPU-Z recognized the CPU and validated it running at 3192.04GHz on a 16x multiplier. During the validated test run, the CPU was operating at just 1.037V. At 3GHz it managed WPrime 1024M in 75.77 seconds.

You can find the thread here.