Superheavyweights-2: Noise and Power Consumption

We discussed the noisiness of top-end multi-GPU systems in our comparative review of Nvidia GeForce GTX 285 3-way SLI and ATI Radeon HD 4870 4-way CrossFireX configurations. And now we will measure the noise produced by an Nvidia Quad SLI platform. Here are the results:

Although the new GeForce GTX 295 is not very noisy, two such cards get quite loud after they have worked long in 3D mode. The noise is quite uncomfortable then. This is no wonder as the bottom card is breathing freely but the top one is placed too close to the other and has problems getting enough of fresh air. The old version of GeForce GTX 295 could get some air through the window in the top PCB, but the new version doesn’t have this opportunity and has to increase its fan speed to avoid overheat. Fortunately, we had no stability issues like with the GeForce GTX 285 3-way SLI, and the tandem passed all of our tests. Still, we want to remind you that a multi-GPU subsystem requires a roomy system case with good ventilation. A system fan on a side panel would help the graphics cards breathe more easily.

Our power consumption testbed cannot test more than one graphics card, so the numbers below are just the total of the results of the respective individual cards in 3D mode.

The real numbers are going to be somewhat different because the power consumption of the Slave card is not zero even in 2D mode, but you can get a general notion of the power consumption of top-end multi-GPU solutions.

A GeForce GTX 295 SLI tandem is going to be more economical than a system with three GeForce GTX 285 cards, but the peak power draw of 400W is not low, even though it is indeed lower than that of the 4-way solution from AMD/ATI. A hypothetical Radeon HD 4890 4-way CrossFireX subsystem would consume over 450W, too.

Again, building a top-end multi-GPU solution with three or four graphics processors is not only expensive but also a noisy and uneconomical business. You should not expect such a subsystem to have a modest power draw. So, if you go in for it, you should purchase a roomy system case as well as a high-quality 750W or higher power supply.