When it comes to testing a power supply, there are two courses to travel. One takes you down a path using a device to stress out the PSU and provide data regarding the power levels across all three rails. The second, and the one I make use of, utilizes an actual test system to give a more real-world account of what the power supply is capable of. While both methods have their merits, I prefer to use an actual computer to more closely resemble the manner of use that you, the potential customer, will put the product through.
That said, let's take a quick look at the test system. At the request of readers, I have beefed up the system to put a more realistic strain on the power supply.
Gigabyte 965P-DS4 motherboard (Supplied by Gigabyte)
Intel Core 2 Duo E6600 processor
2x 1024MB Corsair XMS2-8500-C5 memory (Supplied by Corsair)
GeCube X1900XTX graphics (Supplied by GeCube)
Sapphire X1900XT graphics (Supplied by Sapphire)
Western Digital 250GB SATA hard drive
2x Western Digital 160GB SATA hard drives
Western Digital 80GB hard drive
Sony 52x CD-ROM optical drive
Samsung 16x DVD-R optical drive
2x 120mm fans
4x 80mm fans
While this isn't a Quad-GPU setup, we are certainly in the realm of having a system that is going to put a significant power drain on any power supply. Testing will consist of checking the power levels across all three rails at idle and again while the system is under stress. This should give us a good look at the capabilities of the power supply being tested.
It takes no more than a quick glance to see that even though I don't max this power supply out, the stress that I put on it didn't even cause it to flinch. Dual graphics boards running anything remotely considered to be graphically intensive have brought weaker power supplies to their knees, but the OCZ ProXStream rolls through the test without any drop along the 12v rail. Both the 5v and 3.3v rails dropped by a very small amount, but it is certainly nothing to be concerned about. This power supply showed near perfect stability in all power rails when transitioning from idle to load. Very nice!
The power streams was also very solid. I noted absolutely no fluctuation in readings while monitoring the voltage levels with a multimeter. All readings were rock steady and did not move at all during testing.