Intel recently issued two product notifications that it has cut the power consumption of its Pentium 4 processors.
The PDs will change their CPUID from F64 to F65, and the stepping will be known as D-0, up from the old C-1. The only thing that will affect you is it dropped the power from 130W to 95W, a massive change that is too late in the game to make a difference on the high end.
Affected parts are the 2.8, 3.0 and 3.4GHz non-VT models, and the 3.4 and 3.6GHz VT ones, along with a cryptic hint of an upcoming 3.2 model. The down side, other than the aforementioned hole at 3.2, is the need for a new BIOS to support them.
The single core models will also go on a diet, dropping from 86W TDP to 65W. The stepping follows the dual cores, going from C-1 to D-0, affecting 3.0, 3.4 and 3.6GHz parts, along with the elusive 3.2GHz model. There is no indication of a BIOS change here, but you never know, we might just luck into one later.