Cougar GX-F750W PSU Review

Load Regulation, Hold-Up Time & 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.

Hold-Up Time

Our hold-up time tests are described in detail here.

The hold-up time we measure is over 17ms, though the power-good signal doesn't satisfy the ATX specification's 16ms limit. At least it's accurate.

Inrush Current

For details on our inrush current testing, please click here.

Measured inrush current is on the high side with both voltage inputs.

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the GX-F750's efficiency. The applied load equals (approximately) 10 to 110 percent of the PSU's maximum load 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 0.1A. This test reveals whether a PSU is compatible with Intel's C6/C7 sleep states or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails.

Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed
PSU Noise
Temps (In/Out)PF/AC Volts
14.393A2.004A1.980A0.981A74.78784.018%810 RPM
23.3 dB(A)
29.840A3.011A2.975A1.181A149.80688.902%830 RPM24.4 dB(A)32.46°C0.979
315.637A3.517A3.495A1.380A224.87190.191%885 RPM26.3 dB(A)33.19°C0.979
421.436A4.030A3.984A1.580A299.77390.485%970 RPM29.4 dB(A)33.78°C0.984
526.907A5.041A4.991A1.781A374.74490.305%1070 RPM31.5 dB(A)34.79°C0.988
632.384A6.068A6.006A1.982A449.74189.851%1170 RPM33.9 dB(A)35.49°C0.991
737.840A7.083A7.021A2.186A524.66788.818%1265 RPM36.9 dB(A)36.04°C0.992
843.326A8.114A8.043A2.391A599.65488.095%1390 RPM38.5 dB(A)36.94°C0.994
949.246A8.632A8.580A2.396A674.69887.371%1490 RPM40.5 dB(A)38.49°C0.995
1054.918A9.154A9.086A3.006A749.54686.443%1545 RPM42.2 dB(A)39.35°C0.995
1161.205A9.166A9.102A3.009A824.47485.723%1550 RPM42.7 dB(A)40.42°C0.996
CL10.100A18.030A18.002A0.004A149.90184.143%1190 RPM34.7 dB(A)38.30°C0.978
CL261.948A1.002A1.005A1.002A758.16586.878%1535 RPM41.8 dB(A)39.92°C0.995

The load regulation on all rails is satisfactory. However, it still falls short of this category's top performers. As for the 80 PLUS Gold certification, this PSU satisfies the 20% and 50% load efficiency requirements, but doesn't quite get there under full load. To be fair, this is fairly normal since we test at a much higher temperature than the 80 PLUS organization.

When it comes to noise, the fan spins at 810 RPM under just 75W of load. That's pretty high for such a low load level. It also exceeds 1000 RPM with 50% load, surpassing the 30 dB(A) mark. As mentioned, the fan profile is a bit aggressive. Cougar should relax it a bit in future versions of this PSU.

We we were also troubled by the problems we encountered trying to make the GX-F750 deliver its full capacity at 45°C. Cougar states that this model is rated for continuous full load delivery at 50°C. However, we cannot confirm those claims. In our effort to make the PSU deliver full power or more in our 110% load test at temperatures close to 45°C, we broke the first sample after ignoring its over-temperature protection warnings. So, we decided to be extra gentle with the second one and stay close to 40°C.

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