We reported earlier today that a problem with AMD's quad-core processors has limited supply of "Barcelona" Opterons, but that is only part of the picture. Because the hardware bug—known as an erratum—affects all revisions and clock speeds of AMD's quad-core processors, it affects the newly introduced Phenom 9500 and 9600 processors, as well. And although AMD is no longer shipping quad-core Opterons to major server vendors and general customers, it is shipping Phenoms to large PC builders and distributors. In fact, AMD knew about the erratum before the Phenom product launch...
...AMD claims it has handed off the BIOS workaround to motherboard makers for implementation, and Saucier told us the company's guidance to partners included an enable/disable option in the BIOS. AMD also has plans for an update to its Overdrive overclocking utility for Windows that will allow users to toggle the erratum fix on and off. Saucier said AMD's thinking here is that savvy users may choose higher performance over the relatively small risk of experiencing a system hang due to the TLB problem...
...We don't yet have a BIOS with the workaround to test, but we've already discovered that our Phenom review overstates the performance of the 2.3GHz Phenom. We tested at a 2.3GHz core clock with a 2.0GHz north bridge clock, because AMD told us those speeds were representative of the Phenom 9600. Our production samples of the Phenom 9500 and 9600, however, have north bridge clocks of 1.8GHz. We've already confirmed lower scores in some benchmarks.
Given everything we've learned in the past few days, our review clearly overstates Phenom 9600 performance, as do (more likely than not) other reviews of the product. We can't know entirely by how much, though, until we can test a Phenom system with the TLB erratum workaround applied.