The potential problem affects a number of single-core Opteron 152, 154, 252, 254, 852 and 854 processors manufactured in late 2005 or early 2006, AMD said Friday. The company hasn't seen the problem in production use, but has seen it in a test that combines high processor temperature, high outside temperature, and a large number of floating-point mathematical computations.
AMD said it has added a new screening process at its manufacturing plants to put affected chips into a lower speed category. For example, a 2.8GHz model won't exhibit the problem when running at 2.6GHz, AMD said.
AMD is working with computer makers to track down the chips and is offering free replacements.
The Sunnyvale, Calif.-based chipmaker has made PC processors for years, but only in 2003 entered the server market with the Opteron chip. Server chips typically offer higher performance, withstand higher heat, and have circuitry that lets several communicate in the same computer.
Since the Opteron's debut,, which previously had the vast x86 server market to itself, but . Opteron's performance advantages has won it a place in servers from , Hewlett-Packard and IBM.
After AMD confirmed the problem, it determined the chips had fallen through a "test escape"--a situation in which a flawed chip passes all tests. In other words, the company says the problem lies in testing, not in manufacturing or design.