We started with measuring the power usage of PC's when they are "idle", so on the windows desktop but no other applications being run. As expected the low budget Intel system with a Celeron D and low power graphics uses the least, only 97W in idle mode. The Pentium 4, Pentium D and Core 2 Duo systems all use similar power when idling, between 124 and 136W. The high-end system surprises a bit, with the two X1950 graphics cards in CrossFire the systems uses no less than 186W, so even when not gaming a high-end system with two graphics cards uses almost twice the power a low budget system uses.
The AMD machines do not differ hugely from the Intels, the Sempron machine is slightly better than the Celeron D and uses 89 Watts when idling, the Athlon 64 3000+ stops at 112 Watt and the two X2 machines are virtually the same as the Intel ones 134 and 136 Watts. Also a high-end AMD machine with two cards in SLI gobbles a lot of power when in idle, we measured 213W in the system with two nVidia GeForce 7900 GTX cards!
A lot of users do not switch their machines off when they are not using them, however our test already shows that this is not a very good idea. Even the most energy efficient machine (89W) uses 780 KWh a year when never switched off. A high end gaming machine like we have in our example with a FX-62 and two nVidia cards uses no less than 1865 KWh a year if you leave it on all the time.
Next in line is the power usage when stressing the systems.We tested both 100% CPU usage as well as 100% CPU and graphics usage. It will not come as a surprise that the Celeron D machine does pretty well when 100% stressed, we measured 140 Watt. The Pentium 4 and Pentium D machines use around 180 Watt when we stress the CPU to the maximum and the Core 2 Duo does a bit better with 170 Watt. It is evident that Intels latest core does what it promises, the performance is a lot better than the Pentium 4 and Pentium D, but the system uses less power. The Core 2 Extreme system clearly has the highest usage, we measured 201 Watt at 100% CPU usage.
The AMD budget system did slightly better, it uses 125 Watt, the AMD 64 3000+ uses 138 Watt but we saw a signifcant increase with the X2 machines, they used 185 and 205 Watts. The FX-62 is the clear "winner" in this test, it used a whopping 282 Watt when stressed.
This test shows that even though it is fun to participate in Folding@Home, UD-Grid or RC5-72 distributing computer projects, it does mean that you PC will be running at 100% CPU capacity all the time and therefore use more power. This can cost a lot of money, as the most energy efficient machine uses 1095KWh a year and the high end gaming machine no less than 2470KWh a year!
Distribited Computing migh be fun, but it will cost you a lot of money when doing it all the time!