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Power Consumption

How much juice do these modern beasts suck up when loaded? As discussed earlier, AMD has made some much-appreciated improvements to power consumption of their AM2s. Fortunately, overall system power consumption is extremely easy to test.

We used a P4400 Kill A Watt power meter to measure power draw of the system minus the monitor. We used the same Aero Cool ZeroDBA 620W power supply on all systems tested so as to exclude power supply efficiency differences from the measured platforms. Idle results were read approximately a minute after Windows stopped thrashing at the desktop, whereas Load results were taken with two instances of CPU Burn-in running with error checking disabled.

The highly overclocked (to 4.2 GHz from a stock 3 GHz) D 930-based system uses the most power - a healthy 257W; but the overclocked (to 3.0 GHz from a stock 2.6 GHz) AM2-5000+ is not far behind at 243W.

The overclocked FX-60 (to 2.8 GHz from 2.6 GHz) is a stride or two away at 206W, just ahead of the stock AM2-5000+ at 200W ... the other players follow.

Overclocking SIGNIFICANTLY increases the power consumption (not just the performance) of processors.

The numbers would only go up of course, if more hardware or higher end video cards in SLI/Crossfire were used.

There is also something else of interest here: The AM2 X2 3800+ consumes 5W less under load, and 21W less when idling, than the older socket 939 version. The AM2-5000+ runs 35W cooler than the FX-60 at the same clock rate - even with the FX-60 having twice the L2 cache of the 5000+, leaving us to wonder how much of that difference is due to using DDR2 memory and how much is due to the lower power consumption of the processor.

All in all, AMD is to be congratulated on lowering power consumption on a general platform that already has the advantage.