Power Consumption & Acoustics
We have two final data points to cover before we bring this article to a close. Throughout all of our benchmarking, we monitored how much power our test system was consuming using a power meter and also set up a sound level meter about six inches away from the graphics cards. Our goal was to give you all an idea as to how much power each configuration used and to explain how loud the high-end configurations were under load. Please keep in mind that we were testing total system power consumption, not just the power being drawn by the video card alone.
Please keep in mind that the numbers posted above represent total power consumption for two completely different systems. The NVIDIA based systems were equipped with a different motherboard, and obviously different video cards. We've included the data strictly as a point of reference. The more meaningful comparison is between the single X850XT and dual-X850XT configurations at the top of the chart. As you can see, running two X850XT cards in one system forced the rig to draw much more power; almost 400w under full load.
While our power meter was working overtime, our sound level meter had it easy. Our CPU cooler (ThermalTake SilentBoost K8), PSU (Enermax NoiseTaker), and triple 80mm case fans drowned out most of the noise produced by the video cards. Disregarding the extra noise some cards produced while the test system was going through its POST, there was very little difference between them all. With the pair of Radeon X850XT cards installed, our sound level meter registered a peak of about 72db. A single GeForce 7800 GTX registered about 66db, and with a pair of GTX cards installed, sound levels peaked at about 69db. When we had a pair of 6800 Ultras installed, however, we did see some activity on noise meter's read-out. With a pair of GeForce 6800 Ultras running, sound levels peaked at about 74db.