Power Consumtion, Noise & Temps
We have a few final data points to cover before bringing this article to a close. Throughout all of our benchmarking, we monitored how much power our ATI based CrossFire test system was consuming using a power meter, and also took some notes regarding its noise output and temperatures. Our goal was to give you all an idea as to how much power each configuration used and to explain how loud the configurations were under load. Please keep in mind that we were testing total system power consumption here, not just the power being drawn by the video cards alone.
We set aside our Radeon Xpress 200 reference board in favor of a brand new ECS motherboard, so the numbers presented here should not be compared with previous articles. As you can see, while idling, all of the single card configurations consumed similar amounts of power, which should be expected considering all of the cards run with similar clock speeds, have the same memory compliment, and are equipped with the same 2D engine. And the dual-card CrossFire configurations consumed about ~30 more watts than any single card while idling. Under load, however, the CrossFire rigs consumed much more power than any single card, and the X1900s used much more power than the X1800 XT. Clearly, anyone considering an X1900 or X1900 CrossFire should also make sure they've got a capable power supply. We used an Enermax 565 Watt model throughout all of our testing and didn't have any trouble.
We'd also like to talk a bit about the noise associated with running a pair of X1900 XTs in a single system. As was the case when we first evaluated X1800 CrossFire, when we initially setup our test machine, and powered it up for the first time, it was clearly the loudest system that had ever graced the lab. Upon initial startup, both fans on both X1900s rotated at their maximum speeds, which resulted in a significant amount of noise. Once the drivers were installed, however, the fans on both cards spun-down dramatically and the test system became relatively quiet. In fact, the system was quiet enough to work with daily, without distraction. And throughout out entire testing process, the fans never spun up to their maximum speeds again. To put it simply, except for the initial shock of hearing two X1900s running at full-bore when we first turned on the machine, our X1900 CrossFire test system was relatively quiet, and we would not consider excessive noise an issue at all during normal use.
Lastly, we took some temperature readings using a Mastercool Laser Thermometer at various points around the X1900s to see how much heat the cards were throwing off. In a single card configuration, we found the hottest part of the card to be the area on the back of the card directly behind the GPU. The spot on the back of the card hit temperatures around 58.5oC, and the external plate vents hit 27.5oC. In a dual-card CrossFire configuration, the card at the top of the chassis maintained similar temperatures, but the card at the bottom hit 62.5oC behind its GPU, and each card's fan shroud hit 41oC (top) and 46oC (bottom). Not cool running cards by any means, but the large heatsinks, and coolers that exhaust warm air from the system mean heat shouldn't be an issue in any well ventilated case.