Navigate: Advice Beginners BIOS Guide CPUs Links Mainboards Memory Network Storage Video/Sound Cards Contact Forum SiteMap Sponsors WebNews Home	.	.
Prices: Mainboards ABIT ASUS Chaintech Shuttle Soyo Tyan CPU Intel P4 2.4C-800 P4 2.6C-800 P4 2.8C-800 P4 3.0-800 P4 3.2-800 AMD AthlonXP XP 1700+ XP 2000+ XP 2400+ XP 2500+ XP 2700+ XP 3000+ XP 3200+ Athlon64 Athlon64 3200+ Athlon64 FX-51 Opteron Opteron 240 Opteron 242 Opteron 244 Opteron 246 Memory Corsair Crucial Kingston Mushkin OCZ Search Prices:

LOSTCIRCUITS	SHORTCUTS: How many Hoover Dams? Isolating Power Dual Stress Liner Venice Improvements Test Conditions Power/Temperature Coefficient Idle vs. Burn-In 3D Rendering 3DMarks DOOM3 and Prime95 Overclocking & Conclusions Give Us Some Feedback on this Review
AMD Athlon64 "Venice" May Low Power be with you!
(Review by MS May 2, 2005)

Isolated CPU Power Measurements

By the very nature of computers, most applications pushing the CPU will also add load to other system components, cases in point are the graphics cards (up to 70W) and the system memory (up to 30 W depending on total system memory density). The overall composite power consumption cannot easily be broken down by an arbitrary formula since it will vary depending on factors as simple as the choice of memory components on the modules.

The new Venice core-based Athlon64-3800+

It is, however, fairly simple to isolate the power going to the CPU since all modern mainboards have the power circuitry for the processor isolated from the rest of the mainboard power. That is, the 4- or 8- pin dedicated auxiliary connector is the sole source of power for the CPU and tapping into it will show the power drawn by the CPU only. Needless to say that there is also a coefficient for the VRM, that is, the energy cycle efficiency or ratio between power-in and power-out at the MOSFETs. It is possible to measure the current output directly at the Vcore output, however, the high switching frequency of the VRM makes the hookup somewhat hazardous for the VRM itself since phaseshifts induced by extra capacitance can easily blow up the entire circuitry – as we found out the hard way. Not a pretty sight.

The Contenders

(click image for larger picture)

Clawhammer vs. Newcastle vs. Winchester vs. Venice. Note the 1.40V rating on the Venice core!

For this report, we have four different CPUs based on four different cores. The ClawHammer core, based on the 130 nm process and featuring the 1 MB L2 cache is represented by the Athlon64 4000+. The Newcastle which is similar to the ClawHammer, albeit with 512 kB L2 cache is represented by the Athlon64-3800+. We have another Athlon64 3800+ in the race, this time, however, based on the Venice core with 90 nm copper interconnect and 512 kB L2. All mentioned processors are specked at at 2.4GHz. In addition, we have the first Ahtlon64 based on the 90 nm interconnect process, that is the 3500+, based on the Winchester core and running at 2.2 GHz.

next page: => Strained Silicon =>