So AMD's Phenom revision b2 has a hardware bug, I am sure everyone knew that by now. AMD released an "unofficial patch" some time ago against 2.6.23.8, and updated it for 2.6.24 and 2.6.25 later. Those patches not recommended by AMD, and using them may burn down your house in addition to your computer.

That said, at least several people found the patch useful. Since I was one of those who were stupid enough to buy one of those broken CPUs, I looked into updating the patch a while ago to 2.6.24-19, which is what Ubuntu Hardy uses. Most of the patch applied cleanly, except in the area of i386/x86-64 merges. I am no kernel hacker, but I've done my best to make the patch apply. The result is here. I can't vouch its correctness except that I've been running it for almost a week now with 1-2 virtual machines running most of the time.

Again, before using this you should read through the 2 threads linked above. If it breaks, you get to keep the pieces.