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. I have continued to beef up the system to put a more realistic strain on the power supply.
MSI X48C Platinum motherboard (Supplied by MSI)
Intel Core 2 Duo E6600 processor
2x 1024MB Corsair XMS2-8500-C5 memory (Supplied by Corsair)
Sapphire HD 2900XT graphics board (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
1x 200mm fan
2x 120mm fans
While this isn't a monster graphics setup, we are certainly in the realm of having a system that is going to put a significant power drain on any power supply in this range. The HD 2900XT board is capable of pulling close to 250 watts of power. Testing will consist of checking the power levels across all three rails at idle and again while the system is under load. This should give us a good look at the capabilities of the power supply being tested.
Since this particular power supply is a mid range product, we removed one of the XT2900 video boards. Even so, the single board is capable of drawing a lot of power that can often cause problems with power supplies that are not of a reasonable level of quality. This Xigmatek unit, however, had no issues at all during our testing phase. No matter the load, this thing just kept providing very stable power to all rails.
I also noted that the drop in voltage under load was less than many other power supplies that have been tested in the past. This bodes well for those who want a stable platform for their system. There is plenty of power available and nearly no fluctuation in voltage. During the stress test (system under load), I saw a fluctuation of 0.01v across the 5v rail and no other movement at all in voltage readings.