Load testing the PSU
Load testing the PSU
In the above screenshot you can see the five GPUs we have installed and activated in this PC.
For our test we used several pieces of software including the Cryostasis PhysX Demo and 3Dmark Vantage which allows us to go hard on the GTX 295 (Quad SLI) AND ALSO use Physx on the additional GeForce 275. During the test runs we simply monitor voltage fluctuations and our Watt meter registers maximum load measured.
The reality is harsh though, with all that equipment and tweaks we just could not pass ~700 Watts load. A year or two ago with this very system we'd have passed 800 Watts, without doubt.
Not only do PC components get more efficient, PSUs themselves are becoming more and more efficient and green as well, in the end saving on overall power draw from the wall socket. PSU's moved from 70% (a couple of years ago) towards 80% and now 88% efficiency. That's nearly saving 20% of your Wattage.
Some notes here. Powered down, the PSU consumes very little; we measured 2 Watts only. And again, though we had so much gear plugged into his system, the power consumption remained fairly low, making me believe that 88% power efficiency is very likely.
Great stuff really.
For those interested, you can download the Cryostatis PhysX Demo and give it a try yourself.