Load Regulation, Hold-Up Time And Inrush Current
To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units.
Primary Rails And 5VSB Load Regulation
Load Regulation testing is detailed here.
Our hold-up time tests are described in detail here.
The hold-up time we recorded is much longer than the ATX spec requires, and the power-good signal drops before the rails go out of spec. We're all good here.
For details on our inrush current testing, please click here.
The inrush current measurements are normal with both voltage inputs.
Load Regulation And Efficiency Measurements
The first set of tests reveals the stability of the voltage rails and the PSU's efficiency. The applied load equals (approximately) 10 to 110 percent of the maximum load the supply can handle, in increments of 10 percentage points.
We conducted two additional tests. During the first, we stressed the two minor rails (5V and 3.3V) with a high load, while the load at +12V was only 0.10A. This test reveals whether a PSU is Haswell-ready or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails.
With 20% load, the efficiency looks good. It's notably below the required 92% at 50% load, though. Under full load, efficiency is very close to the 80 PLUS Platinum specification's 89% requirement. Frankly, we expected higher efficiency at mid-load. Then again, high operating temperatures increase energy losses, so we should expect to see efficiency take a hit in our taxing test environment.
Load regulation is fairly tight on each rail except 5VSB, while the PSU operates in fanless mode at up to the 40% load test. The fan rotates at its lowest speed in the following four tests, while at 90% load and up the fan's noise starts to get annoying. You really have to push the PSU at its limits to make the fan spin at full speed though. At that point, our measurement equipment registers greater than 50 dB(A). Again, we think the fan control circuit should be more granular.