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.
Our experience so far dictates that ACRF topologies are capable of high hold-up times; the 750 GQ is definitely not an exception, since it achieves 24.8ms. In addition, the power good (PWR_OK) signal follows the ATX spec's requirement and drops before the rails go out of spec. Very good performance here!
For details on our inrush current testing, please click here.
The NTC thermistor is very small, resulting in increased inrush current with both 115V and 230V input. EVGA should probably use a larger thermistor for this purpose. It wouldn't affect the PSU's efficiency since there is a diode bypass when the start-up phase finishes.
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.
|Test #||12V||5V||3.3V||5VSB||DC/AC (Watts)||Efficiency||Fan Speed (RPM)||Noise (dB[A])||Temps (In/Out)||PF/AC Volts|
Load regulation at +12V is tight enough, though it doesn't stand up to EVGA's 750 G2. The same goes for the 5V rail, while the 3.3V rail is on the loose side with close to 3 percent deviation. Lastly, the 5VSB rail surprises us with tight load regulation, at least for that rail's standards.
As you can see from the noise output column, the PSU runs passively up to our 30% load test, yielding silent operation. At 40 percent load, the fan starts spinning slowly. It takes a 60 percent load for the noise to become noticeable. The noise increases quickly as the load increases. In our worst-case test, the fan screamed along, annoying anyone in its vicinity. FSP definitely uses a high-speed fan, and although it spins slowly in most cases, when you push the PSU it makes a ton of noise.
We left the efficiency performance for last. It's very good under light and moderate loads, but then drops below the specified limit during our full load test. Given the almost 47 °C ambient environment we used, though, we'll give EVGA a pass, especially since the 80 Plus organization conducts its tests at only 23 °C.