Some AMD Opteron processors have a floating-point bug

Posted on Saturday, April 29 2006 @ 0:07 CEST by Thomas De Maesschalck
The Register writes AMD admitted it has inadvertently shipped a number of 2.6GHz and 2.8GHz single-core Opteron x52 and x54 processors that could generate inconsistent results under extreme conditions.
It is believed that the glitch is triggered when the affected chip's FPU is made to loop through a series of memory-fetch, multiplication and addition operations without any condition checks on the result of the calculations. The loop has to run over and over again for long enough to cause localised heating which - and here's the real problem - causes the result of the operation to be recorded incorrectly, leading to data corruption.

To trigger the bug, the loop has to be run millions of time, the source said, potentially for hours at a time, and no other operations being introduced during the run.
More info over here.

Loading Comments