Corsair HX1000W PSU

Results

We cannot fault the quality of product Corsair has here as every voltage is green and well within ATX spec. For the most part it's an excellent 87 percent efficiency with a very high PFC, and only a couple of percent efficiency is lost in the 12V to 3.3V/5V conversion when we weighted the load onto them.

During testing we found that at 50 percent load the unit was cool and very quiet, but not silent, and the sides, base and air out the back was cool to touch. As this was increased to 75 percent load and left to warm for a while the noise increased quite substantially and the air out the back became warm to touch. The base and back was also now warm, although not hot, and interestingly one side was warmer than the other even though we had loaded both 12V rails pretty evenly.

As we increased this to 100 percent load the noise again substantially increased and the unit became a little warmer again but not hot. The air coming out the back did become notably hotter though. We left it for a while to sit at full load and it sat quite happily without further increments in temperature and noise, however it was already noisy enough. The combination of obvious ball bearing noise and gushing air was very intrusive to the environment, even when we had some huge fans in the test units kicking it up a notch to keep up the provision of power. Compared to other 1,000W models it's not unexpected - you'll not yet find a "silent" kilowatt power supply, after all, even at 87 percent efficiency it has 150W of wasted heat to dissipate and most older models barely scratch much over 80 percent so that's 250W of excess heat.

The thing is with these CWT models is that we test at 20-25C, not a normal case temperature which is more ~40-50C depending on how much hardware you have crammed in a tiny space. Corsair does rate this product at 50C with a "100k" hours MTBF , which is certainly better than others at 40C or 25C, even if the "100k" is nothing more than an arbitrary value.

The rail weighting is split evenly between the ATX, EPS 12V and half the PCI-Express on one and the modular cables for peripherals and the rest of the PCI-Express on the other. It makes sense to do it this way and it works because there's plenty of 12V to go round and as you add devices it increases pretty evenly across both 12V rails.