On Friday 08 April 2005 18:43, p k wrote: > > A benchmark that is becoming more and more prevelant is cpu performance per > watt. > > AMD processors use much less energy and also run much cooler than Intel > procs.
An Intel 4.77 MHz 8086 uses much less energy than any current AMD processor, and runs so cool it doesn't need even a passive heatsink. OK, I know what you mean, but "performance per watt" depends a lot on how you measure performance. Prime95 is particularly effective at making use of SSE2 which multiplies its Prime95 performance rating considerably compared with Athlons. In any case, in my experience the most expensive component in the energy budget is the power supply. Very few desktop computer PSUs are constructed with efficiency in mind; conversion efficiencies as low as 30% are common, especially in the cheaper units found in mass-market systems. Laptop PSUs tend to be better in this respect, though unreasonably warm bricks are far from unknown. > > The Pentium 4 vs. Pentium D comparison is also interesting, as the 2nd core > doesn't add all that much to overall system power consumption. In this > case, we're looking at an increase in overall system power consumption by > less than 15%. If it's going to do real work, it's going to consume real power. Stuffing a second core into the same thermal package, without doing something about the losses which have afflicted Prescotts much more than Northwoods, is just going to make the thing heat up faster. Being a P4 it will just throttle - at which point you will have two half-power CPUs instead of one full-power CPU. The Register mini-review of a Pentium D system actually found little difference in benchmarks between 3.2 MHz P4D and 3.4 MHz P4EE systems. I wonder if thermal effects might have been kicking in. http://www.theregister.co.uk/2005/04/05/review_intel_pentium_dual-core/ Regards Brian Beesley _______________________________________________ Prime mailing list [email protected] http://hogranch.com/mailman/listinfo/prime
