Loading up The Beast
A cornerstone of our power supply testing methodology is a custom-built load generator created by forum regular justbrewit that we like to call The Beast. If you're unfamiliar with its frightening array of resistors, I strongly suggest checking out this page of our last PSU round-up, which details the rig's internals and our testing methodology.

Behold The Beast!

We use The Beast to push each PSU to 25, 50, 75, and 100% of its output capacity while measuring DC voltage, AC ripple content, and gathering data that can be used to calculate overall efficiency. However, since The Beast is limited to applying loads in 2A increments, we borrow a page from The Price is Right and use amperage loads that come as close as possible to our targets without going over. The chart below shows the amperage loads applied to each PSU.

When testing with The Beast, each power supply was hooked up using its primary and auxiliary 12V connectors, two PCIe power connectors, and six four-pin peripheral connectors. We used a Pico ADC-212 digital oscilloscope to probe the 3.3 and 5V wires on the primary power connector. 12V lines were probed in the primary power connector and also with one of the PCIe power connectors. In the graphs on the following pages, 12V power from the primary connector will be marked 12V1, while power from the PCIe connector will be 12V2.

Apart from additional testing at 25% capacity, our methodology is largely identical to what was used in our last PSU round-up. However, we have tweaked our efficiency calculations a little to use actual average DC voltages along the 3.3, 5, and 12V (from the primary power connector) instead of arbitrary 3.3, 5, and 12V values. That should give us more accurate results and compensate for any voltage sagging under load.

Our testing methods
Testing was conducted in two parts. First, PSUs were run in the system detailed below for a series of power draw, temperature, and noise level tests. They were then hooked up to The Beast to test power delivery and overall efficiency.

All tests were run three times, and their results were averaged.

We used the following versions of our test applications:

• The Elder Scrolls IV: Oblivion 1.1
• Intel IOMeter v2004.07.30
• Prime95 v24

The test systems' Windows desktop was set at 1280x1024 in 32-bit color at an 85Hz screen refresh rate. Vertical refresh sync (vsync) was disabled for all tests.

All the tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.