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 is 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!
Overall we are seeing some very nice numbers here. While the 12v rail is slightly lower than its rated value, there are no areas of concern and the system stability was strong no matter what I did. Even Overclocking processor and graphics made no difference to the load results, so we have a very stable line of power to work with here.
Also of note is the overall stability of the power along all rails. I monitored both at idle and under load and all three rails showed fluctuations of either zero or .001v, so the power is strong and stable across the board. Why is the signal so stable?
Mushkin uses a multi-rail setup for the 12v rail. There are actually four 12v power rails within the unit. While multiple rails is somewhat common nowadays, they also use what they refer to as "Rail Fusion", which allows the power supply to automatically supplement another 12v rail that is getting close to its capacity. This ensures a steady flow of power along the rail that is generally the most abused in any modern system. For those who like the numbers, the 12v rail has a maximum output of 44A.
