The problem is that Prescott is not yielding parts that run at 1066MHz FSB. The chipsets have been ready for months, but there is nothing to run on them. The 1066 parts were pushed back and pushed back, and now they are to become a boutique part, the EE line.Could it be that the CPUs themselves won't consistently tolerate a 1066MHz bus? Given all the other problems with Prescott, including the recent decision to drop plans for a 4GHz version, I certainly wouldn't dismiss the possibility too casually. This is certainly the best explanation we've heard so far for why the P4 600 series with 2MB L2 cache is expected to debut with an 800MHz bus. Then again, I've cranked a Prescott up to a 1.02GHz bus speed with relatively little drama, so who knows?
The mainstream 1066 FSB parts are now set for mid-year 2005, and that goal is not looking good either. The current plan is to have 3.46GHz EE parts soon and 3.73GHz parts before the end of the year.