According to The Inquirer, AMD has decided to recall a few thousand Opteron x52s and x54s processors because the units may have a temperature induced FP bug.

When the chips get hot, and you are running FP heavy code, you get 'inconsistent' results.

AMD declared that there are a small number of chips - about 3000 - and it has a test that can identify the chips. If you are affected, it will replace the chips for free.

This news article was written on April 29, 2006, quoting The Inquirer.