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Power Usage

To measure power usage, we used a Kill A Watt P4400 power meter. Note that the above numbers represent the power drain for the entire benchmarking system, not just the video cards themselves. For the 'idle' readings we measured the power drain from the desktop, with no applications running; for the 'load' situation, we ran a demanding part of 3DMark06.

Here are some power usage numbers for your consideration. ATI recommends a 600W or greater power supply for running multiple HD 4000 cards. Of course, if you have a budget 600W PSU you might be pushing things; and if you wanted to use three cards in your system, going with a 800W PSU or greater would not be a bad idea. 

Conclusion

In September of 2007 I wrote a Vista-based SLI versus CrossFire article. At that time, multi-GPU support was fairly new for Vista. In that article, SLI showed significantly more promise than CrossFire did. In the intervening time, CrossFire has come a long way, but unfortunately, it still has a long way to go. 

You can see the performance potential in Call of Juarez -- when CrossFire in Vista really works, it really works. But while the HD 4870 and HD 4850 are very impressive video cards, overall, their CrossFire performance in Vista is not nearly as stellar. Besides the driver installation troubles, Catalyst 8.7 Crossfire performance in Vista is really a hit-or-miss affair. As said earlier, half of our benchmarks did not even run without excessive crashes, and the for the programs that did run, only a few really benefited from multiple video cards.

From this initial testing, picking up multiple ATI video cards can not be recommended if you are gaming in Vista -- it looks like far too many gamers would be disappointed with the results, and lack of scaling, at this juncture. The potential is there but right now it's a pie in the sky and the pie is awfully high, in that metaphorical sky.

It should be very interesting to see how the HD 4870 X2 will perform. The video card is rumored to be coming sometime next month. No doubt its performance will be limited by the Vista drivers, and not the silicon. There is not all that much to complain about when it comes to the HD3870X2's performance in Vista right now, so we here at Neoseeker are optimistic things will turn out. It just may be a bumpy road at first for the early adopters.

Disclaimer: We can only report on the results we have gathered through our testing. Perhaps with a different motherboard, or a different Vista configuration,  you may have better luck.