6 - Load Testing the PSU

Load testing the PSU

Load testing a PSU in theory it's not that difficult, but once you reach a 600+ Watt PSU, that's theory becomes a little more difficult. As you actually need gear to be able to reproduce such Wattage.

Fact is that we do not have the gear in house to be able to stress this PSU to it's full capacity the way we should, load-testers costs thousands of euro's.

What we however can do is build an energy sucking beast of a PC, pretty easily. So here's what we did. We took:

• eVGA Force 750i ULTRA SLI FTW mainboard (consumes heaps of current)
• Core 2 Quad QX9770 Processor (at 3.6 GHz)
• 2Gb DDR2 memory at 1142 MHz
• 2x GeForce 9800 GX2

So to stress everything a little more we overclocked the CPU cores towards 3.6 GHz, had the DDR2 memory running at 1147 MHz.

Why do we overclock? Two reasons really, overclocking will result in higher power consumption which is what we are looking for. Yet a secondary side effect of overclocking is that it also requires a really stable power supply. If you have all the components right, yet can't succeed in overclocking your PC, chances are that you either blow at tweaking ... or your PSU is just not up-to speed with what you want to achieve.

For the load test we simply use Call of Duty 4, enable high IQ settings and have a go with it at 1600x1200 which is a good balance between maxing out the graphics cards and the processor cores utilized. See we try to replicate the stuff you guys do at home ... that's what we think counts.

Our test is pretty nasty on graphics cards; it makes them sweat as we'll certainly force all GPU cores to 100%. Now with one GeForce 9800 GX2 I realized that we're stressing the PSU slightly, so we added another one of them (Quad SLI) and will render the game with four active GPUs. We also added some extra fan's, lighting and water-cooling.

Top of the line high-end, agreed? Good, let's tap some voltage eager rails. While the system is IDLE en then fully at work (load).

Some examples: the 5 volts rail monitored, tapped from the HDD.

The 12V2 volts rail monitored. Very constant levels. We do the same for the GPUs 12v lines by tapping the PCIe power connector. I couldn't take a photo as I need to use both hands to tap them carefully.