Specifically, AMD has found a bug in the translation-lookaside buffer, which can impact some of AMD's quad-core chips. AMD will rework both chips and provide a new stepping, sources said, but in the meantime motherboard manufacturers are being asked to distribute a BIOS patch that, unfortunately, reportedly cuts performance by about 10 percent.
"You may remember that during our Q3 earnings call, AMD acknowledged that our initial ramp of Barcelona had been slower than anticipated," AMD spokesman Phil Hughes said in an emailed statement. "However we did say during that call that we would ship 'hundreds of thousands of quad-core processors' into the server and desktop segments during Q4. AMD is tracking to this guidance. Quad Core AMD Opteron processor is the most advanced x86 processor ever introduced to the market and as such there are design and process tuning steps that will take longer than expected.
"There has been some talk about an erratum relative to our TLB cache in Barcelona as well as Phenom processors resulting in delays," Hughes added. "AMD notified customers of this erratum and released a BIOS fix prior to the Nov. 19th launch that resolves it. We are experiencing strong AMD Phenom demand and are shipping parts to channel, system builders and OEM customers."
Both of AMD's existing Phenom parts – the Phenom 9600 and 9500 – run at 2.3 GHz and 2.2 GHz, respectively. AMD's Phenom 9900, which runs at 2.6 GHz, is due in March 2008. AMD's Hughes said that the BIOS fix was distributed to motherboard makers as part of the Phenom launch.