System temperatures
Our next batch of tests deployed the PSUs in a real-world system with a pair of GeForce 8800 GTS cards in SLI and a couple of hard drives. For these tests, the systems first sat at idle for 10 minutes. They were then subjected to a 10-minute load consisting of Prime95, Oblivion, and an IOMeter file server test pattern.

System temperatures were measured using a combination of Nvidia's nTune system utility for the GPUs and Asus' PC Probe software for the CPU and motherboard.

The Infiniti's beefy 140mm fan helps it maintain the lowest temperatures at idle, occasionally by large margins over the rest of the field. Models with 80mm cooling fans didn't do so well here, with the EarthWatts struggling the most. Even the mighty Silencer runs the system a little warm.

Under load, the differences in temperatures between the PSUs shrink, and the Infiniti loses its hold on the lead. It's hard to pick an overall winner, particularly because motherboard and GPU temperatures are so close. However, we see nearly a 10-degree spread in CPU temperatures, with the EarthWatts trailing by a full three degrees alone.

The Toughpower, Infiniti, and 550W Real Power Pro enable the lowest CPU temperatures here. Interestingly, the 650W Real Power Pro leaves the CPU five degrees warmer than its lower-wattage counterpart.