I've been playing with power supplies for quite a while now and I guess in my old age, I like to sometimes make things interesting. My normal method of testing a PSU was to get the system up and running, get a burning session on a CD-RW running in the background, then cranking up something along the lines of Quake 4 and run a long-winded demo. Once everything is cranked up, I'll measure the voltage levels along the power rails to see how close they remain to specifications. The thought behind this method of testing is to see if the power supply can maintain acceptable power levels while under stress.
While I will continue to use this methodology, I also decided to compare these results with the power levels at system idle just to see how much the unit drops off while the system is under a load. This should give us a little more in depth picture of what the PSU in question is capable of. After all, with power supplies becoming a very important component in modern computers, it pays to know ahead of time what works and what doesn't.
But before we dig into the multimeter readings, lets take a quick look at the test system being used:
DFI LANParty UT nF4 Ultra-D motherboard (nVidia nForce4 Ultra chipset)
AMD Athlon FX-53 processor (Supplied by Newegg.com)
2x 512MB Mushkin "Redline" PC3200 memory (Supplied by Mushkin)
GeCube X1900XTX graphics card (Supplied by GeCube)
Four case fans + Thermaltake CPU cooler using 80mm x 38mm high performance fan
All right then... the system is running and the tasks are chugging along. The processor is at default speed and voltage is set to 1.5v. The memory is running at 2.9v and all other levels are set to default. The motherboard is an absolute power hog and the video card has sent many lesser power supplies to an early grave. Let's see what this thing can do!
As the graph shows above, all power rails maintain a very steady voltage level at all times. While I have certainly tested power supplies that have gone to higher levels, few have managed to maintain this consistent of a power flow between idle and stress conditions. While monitoring the voltage levels, both the 3.3v and 5v rails were rock steady. The 12v rail showed small fluctuations, but nothing more than 0.02v movement.
As a side note, I did my normal testing step and ran the test system for a week under varying stress conditions and I never noted any times of instability. Overall, this should prove to be a solid contender if you happen to be looking for a 600 watt range power supply.