AMd is apparently facing supply problems with their quad-core Opteron processors, and it’s rumored to trace back to errata in the L3 cache of the design:

“AMD’s quad-core “Barcelona” Opterons have been notably difficult to find since their introduction two months ago, and The Tech Report has learned that a chip-level problem has impacted the supply of these chips to both server OEMs and distribution channel customers.

Chipmakers refer to chip-level problems as errata. Errata are fairly common in microprocessors, though they vary in nature and severity. This particular erratum first became widely known when AMD attributed the delay of the 2.4GHz version of its Phenom desktop processor to the problem. Not much is known about the specifics of the erratum, but it is related to the translation lookaside buffer (TLB) in the processor’s L3 cache. The erratum can cause a system hang with certain software workloads. The issue occurs very rarely, and thus was not caught by AMD’s usual qualification testing.”

Read the rest of the article here