CES 2008: AMD's B3 Stepping Failed to Fix The TLB Errata

Chip manufacturer Advanced Micro Devices keeps on failing the users' trust test, just like it did last year. We have reported during the last year about the Phenoms and Barcelonas being affected by the Translation Lookaside Buffer erratum, an issue that leads to system freeze when the CPU reaches full load, especially in virtualized environments or during nested page memory operations.

All the processors in AMD's K10 CPU family are sharing a L3 cache pool that keeps essential data as close to the processor's cores as possible for faster access. When the software is using nested memory pages, a race condition will occur, and the error will prevent the memory arbiter to correctly handle it.

The erratum is also known as Intel's F00F bug, and has been widely documented since Phenom's official launch date. The manufacturer has also released a microcode injection patch, alleged to heal Phenom's uncontrolled behavior at speeds higher than 2.4 GHz. Unfortunately for AMD, the microcode does not solve much of the processor's trouble, and if it does, CPU's performance will be cut down 10 percent.

AMD has estimated that the issue will be fixed in processors' next revision, called the B3 stepping. Rumor has it that they are far from being true. Hardware French site Erenumerique reports that it learned, during a discussion with the AMD representatives, that the company has just received the first Phenom B3 silicon. It seems that the B3 stepping was affected by the same TLB issue during the internal tests.

Moreover, the company has been reported to go on with a "new spin" of the silicon, but at this moment we cannot figure out whether it will be regarded as the B4 stepping or it will be just a B3 correction. The French site reported that the B3 silicon will not be ready until May 2008.

This might be the true reason behind AMD's decision of delaying yet again the Phenom 9700 and Phenom 9900 to the second quarter of the year. It's just a supposition, but that's better than AMD's big nothin' they constantly provide.