We have one final data point we'd like to cover before bringing this article to a close. Our goal was to give you all an idea as to how much power each configuration used while idling and running under load.
Please keep in mind that we were testing total system power consumption here at the outlet, not just the power being drawn by the processors alone. In this test we're showing you a ramp-up of power from idle on the desktop to full CPU load and then a ramp to full CPU and Graphics load. We tested with a combination of Prime 95 and Folding@Home on the CPU and then eventually added in RTHDRIBL (the DX9 Real-Time High-Dynamic Range Image-Based Lighting test) to stress the our dual-GPU subsystems.
Tests Performed With Athlon 64 FX-62 And GeForce 7900GTX Installed
Here we're comparing only the ATI CrossFire Xpress 3200 for AM2 reference board versus the Asus M2N32 SLI Deluxe based on the NVIDIA nForce 590 SLI chipset. As you can see, whether at full CPU or full CPU and GPU load, the NF590 SLI system drew about 40 watts more power over all. Next we'll compare some of these peak numbers to a similarly configured Intel Pentium EE 965 and 975X chipset-based system.
Interestingly enough, at full load the Pentium EE 965 system consumed slightly less power overall versus the FX-62 on nForce 590. However the CrossFire Xpress 3200 AM2 (RD580) system showed a 35 watt power consumption advantage over Intel's flagship. Incidentally, temperature readings taken with an infrared thermometer on the power array and chipset heatsinks, showed the RD580 ran about 10-15oC cooler then the nForce 590 SLI as well.