Speculation about Prescott is thriving on the net, and quite a few newsbits are a bit off as they base their information on prequalification CPUs. First of all, the prequalification Prescott CPUs, such as the 2.8 GHz samples which have been reviewed on a few sites, are indeed pretty hot CPUs, much hotter than the real qualified production Prescott CPUs. Still, Prescott will of course not be a competitor to the Pentium-M, as we can read in this Intel document (page 13):
Intel® Pentium® 4 processors, this includes full electrical support of 70 A Icc_max specifications and robust cooling solutions to support 63 A thermal design current (TDC) indefinitely within the envelope of system operating conditions.
For processor code named Prescott, this includes full electrical support of 78 A Icc_max specifications and robust cooling solutions to support 68 A thermal design current (VRTDC) indefinitely within the envelope of system operating conditions.
So what does this mean? The 68 A is a maximum TDP current that the Prescott requires, the 78 A seems a peak value. I wasn't sure how this translates into power dissipation, but "Slee" explains it all here:
"Based on previous Intel documentation, 68A is slightly more than the maximum sustained current that was observed using a large suite of applications. In other words, it is highly unlikely that any useful realworld application will ever exceed 68A sustained. 78A is the maximum current that can occur but its not sustained. Therefore, depending on the voltage of Prescott, we have a thermal design (real world maximum) power of ~82W, with a maximum power of ~93W for 1.3V, or 75.5W TDP and 86W max for a core voltage of 1.2V. A far cry from the 103W rumors that still exist today. Also, since this is the design document for S478 Prescotts, it could be expected that this is the thermal envelope for the entire range of S478 Prescotts, for 3.4GHz or maybe even 3.6GHz."
To give you an idea of how this all compares, here are some (absolute) maximum power values:
* 0.13 µ SOI Athlon 64 3200+ (2 GHz) : 70 Watt
* 0.13 µ Athlon XP 3200+ (2.2 GHz): 76.8 Watt
* 0.13 µ Pentium 4 2.8 GHz: 85 Watt
* 0.13 µ Pentium 4 3.06 GHz: 100-105 Watt
* 0.09 µ Pentium 4 "Prescott" 3.4 GHz: 86-93W
So what about the 78 A value? I also found an interesting comment from Groo:
"This is for their P4 EE chip's 'Hot and Searing' feature. It is meant for short bursts to make your player run faster, or to brand the Intel logo on hardcore gamers."
A new kind of overdrive?