Advanced Micro Devices Inc (AMD)

[pgerassi]

Take your "comparisons" one by one.

The first compares a uATX board with minimal on board capabilities against a capable, quite featured, full ATX A8V. Like only 2 DIMM slots 855GME versus 4 DIMMs for the A8V. PC2700 speeds versus PC3200 speeds. No third IDE channel. 2 SATA ports versus 4 SATA ports. No firewire ports. 2CH audio versus 8CH audio. 10/100 Ethernet vs 10/100/1000 Ethernet. No Cool&Quiet for AMD, but PM could use its internal shutoffs. Higher capable power circuits on the A8V so it can run A64FX 55 with 3PH power versus 2PH power on the 855. Dual channel A8V pushes DDR harder than single channel 855 does. Lastly, A64 can push the graphics harder and push its power use up. Oh and they used a Winchester and not the current Venice. And overclocking may have been with a "cherry picked" CPU versus 2.4GHz Venices that are now "off the shelf". Venices and San Diegos typically overclock to 2.7GHz on air.

The second compares two low end boards, the 855 and 865PE versus a top end Nforce4 SLI with tons of features. Again only 2 DIMM slots versus 4 slots for the SLI. No RAID either for the 2 IDEs or 2 SATA ports on the 855/865, but available for the 2 IDEs and 8 SATA on the SLI. 10/100 Ethernet versus 2 10/100/1000 Ethernet ports. 2 SLI PCIe ports versus AGP only. Ditto on Geforce 6800 Ultra which needs a PCIe/AGP bridge for the SLI vs the 855/865 which uses it in its native AGP form. 2CH sound versus 8CH sound. Firewire missing. No firewall for Ethernet. Higher available power on the SLI versus the 855/865. Dual channel DDR vs single channel on the 855/865. All of these high end desktop stff takes power that PM doesn't have and can't really use. The 865 does have more stuff and uses 11W/9W idle/load than the 855 for the same 2GHz PM. This should server as a wakeup call that MB has a large effect. When looked at the 12V input to the CPU power circuits, A64 Winchester does much better wrt the PM (I forget which site did this, but the reference below uses an even better method, direct measurement of the VRM output (V*I)). Venice does even better than Winchester. But, you don't like to cite those references that use those methods.

Take another look and going from 2GHz to 2.13GHz uses 6W both at idle and full load. The A64 2GHz to 2.2GHz uses only 2W/5W idle/load for the 90nm Winchester. Scaling A64 to a 6.5% clock increase would be just 1.5W/3.3W vs 6W or 25%/55%. Enabling Cool&Quiet will likely show just how much power is used in those ancillary circuits on the MB as Winchester uses less than 3W in that mode. Performance number needs to take into consideration that FSB is at 130MHz for the OC Dothan likely making AGP run at 87MHz. This has been shown to boost gaming numbers. NF4-SLI locks PCIe and PCI at the normal levels.

Last reference shows no graph for power levels but given those numbers that they cite, likely is again measuring wall plug power. That is not like the direct measure used by Lost Circuits in the references below.

As for my numbers, I used http://www.sandpile.org and a few articles like http://www.lostcircuits.com/cpu/amd_venice/ , http://www.lostcircuits.com/cpu/amd_x2/ and of course datasheets like http://developer.intel.com/design/mobile/datashts/305262.htm .

By that datasheet and using AMD's methods for calculating TDPmax (Sum(Izmax*Vzmax) for all supplies z), you get 40W TDPmax for the Pentium M 770 (2.13GHz@533FSB) (Used Vcc, Vcca and Vccp). Intel uses 3 milliohm VRM series resistance to lower TDPtyps, AMD uses a value of 0 milliohms. I do this to use apples to apples comparisons. Of course you need to look at the datasheet of the NB (855PM: http://www.intel.com/design/chipsets/datashts/252613.htm ) to try to pick out the FSB switch and DDR controller power to match TDPs (I estimate 8.9W TDPmax).

Without this, 2.13GHz Dothan uses more power than either MT or ML Turions and 35W TDPmax Turion ML-37 is already at 2.2GHz. Before Dothan gets to 2.26GHz some time next year (highest on current roadmap is 2.13GHz 770 at least till December 2005), ML-40 will be out at 2.4GHz and 25W TDPmax MT-37 at 2.2GHz. Here is speculation that Yonah will get to 2.5GHz: http://news.softpedia.com/news/Intel-s-Yonah-could-run-at-2-5-GHz-056.shtml . Another poster at Ace's Hardware states that Intel specifies that Yonah will be at 2GHz at 31W and 1.67GHz at 15W ( http://www.theinquirer.net/?article=22508 ), but this looks like a server successor, Sossaman H1?/06. Others have it at 2.17GHz @ 667FSB x50 ( http://www.vr-zone.com/?i=2142&s=1 ) no word on TDP target. But the 780 PM is no longer on the 2H05 roadmap.