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. We tested with a combination of Cinebench 9.5 and SANDRA XI on the CPU.
* PLEASE NOTE: QuadFX FX-74 Tested with and without Cool n' Quiet
Before you look at this graph and gasp at the overall power draw of the QuadFX systems, we have some explaining to do. The QuadFX rigs listed here were assembled in a full tower case that incorporated multiple intake and exhaust fans. The QuadFX systems also had three additional cooling fans mounted at various locations on the motherboard, dual-optical drives, a floppy drive, and a 1 Kilowatt PC Power & Cooling PSU. Due to the dual-socket nature of QuadFX, the systems were also equipped with four memory DIMMs versus two on the other systems, and they of course had two CPU coolers as well (In case you're wondering, yes, the QuadFX rig was incredibly loud with all these fans).
Our other tests systems were equipped with different PSUs, no additional cooling fans, only two DIMMs, and only a single optical drive. These differences in the configurations, along with the over-the-top nature of the QuadFX platform itself account for the huge power consumption deltas you see here. No matter how you slice it though, QuadFX is going to be a monster in terms of power consumption. Enabling Cool 'n' Quiet brought idle power consumption way down from over 400W to a much more palatable 260W, but relatively speaking the QuadFX platform is much more power hungry than Intel's Quad-Core QX6700 desktop platform.
It's interesting to note the differences in consumption on the different platforms under idle and load conditions, however. The Core 2 Extreme QX6700 for example, consumed 96 more watts under load than at idle. The QuadFX FX-74 based rig consumed 100 more watts, the FX-72 91 more watts, and the FX-70 86 more. This shows the processors themselves to be on a similar level in terms of power consumption, but the complexity of the QuadFX platform as a whole requires significantly larger amounts of power to achieve similar, albeit somewhat lower performance, than Intel's current quad-core platform.