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Corsair CX750M PSU Review

Corsair's CX line is aimed at users with limited budgets who still want a branded, reliable, and well-supported PSU. Today we're reviewing the second-strongest member of the family, the CX750M.

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.

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Hold-Up Time

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

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The hold-up time we measured is very low. Normally it should be at least 17ms; in this case it dips under 10ms. The only redemption comes from the power-good signal dropping before the rails go out of spec. Still, Corsair should use a larger bulk cap to increase the CX750M's unit's hold-up time.

Inrush Current

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

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Inrush current registers on the high side, especially with 115V input. We would like to see readings under 50A.

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the CX750M'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 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 #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan SpeedFan NoiseTemps (In/Out)PF/AC Volts
14.408A1.983A1.995A0.991A74.8079.25%760 RPM25.2 dB(A)37.29°C0.982
12.077V5.039V3.303V5.031V94.3940.54°C115.1V
29.866A2.978A3.003A1.196A149.7884.82%760 RPM25.2 dB(A)37.76°C0.983
12.054V5.026V3.294V5.013V176.5842.12°C115.1V
315.695A3.486A3.524A1.400A224.8986.54%760 RPM25.2 dB(A)38.92°C0.990
12.031V5.017V3.288V4.994V259.8744.70°C115.1V
421.541A3.993A4.020A1.606A299.8087.05%760 RPM25.2 dB(A)40.21°C0.993
12.006V5.008V3.281V4.976V344.4147.29°C115.1V
527.067A4.998A5.040A1.814A374.7386.67%970 RPM32.3 dB(A)41.86°C0.995
11.981V4.993V3.273V4.956V432.3749.83°C115.1V
632.609A6.024A6.064A2.023A449.7486.00%1180 RPM38.1 dB(A)42.66°C0.996
11.957V4.985V3.267V4.938V522.9751.29°C115.1V
738.182A7.041A7.095A2.235A524.6685.06%1375 RPM42.3 dB(A)43.41°C0.997
11.930V4.975V3.261V4.916V616.8452.91°C115.1V
843.770A8.077A8.133A2.450A599.6583.92%1610 RPM45.2 dB(A)44.58°C0.997
11.905V4.963V3.257V4.895V714.5954.56°C115.1V
949.834A8.595A8.673A2.455A674.7182.51%1705 RPM46.8 dB(A)44.85°C0.997
11.878V4.953V3.254V4.882V817.7855.19°C115.1V
1055.643A9.122A9.190A3.090A749.6381.17%1925 RPM49.2 dB(A)45.82°C0.997
11.855V4.947V3.250V4.851V923.5857.30°C115.1V
1162.072A9.132A9.207A3.097A824.4479.71%2070 RPM50.9 dB(A)46.07°C0.998
11.832V4.942V3.246V4.839V1034.2657.93°C115.1V
CL10.100A15.980A15.986A0.001A132.2378.92%760 RPM25.2 dB(A)43.67°C0.982
12.046V4.937V3.261V5.028V167.5551.12°C115.1V
CL261.943A1.001A1.003A1.002A747.6082.00%1965 RPM49.7 dB(A)46.91°C0.998
11.856V4.996V3.263V4.918V911.7658.72°C115.1V

Load regulation is decent, though not as good as the CX650M. The same goes for efficiency. It is obvious that this platform can't offer the same performance as the smaller CX-M models, and that's disappointing since we expected performance to go the other direction. To make matters worse, the 80 PLUS Bronze requirement of at least 82% efficiency under full load isn't met; this PSU barely passes 81% efficiency in that test. As usual, we have to concede that 80 PLUS conducts its measurements at a very low ambient temperature, whereas ours was a more realistic 46°C. It's natural to measure lower efficiency in warmer environments.

Output noise is pretty low up to around 40% load. Similar to the CX650M, though, Corsair's minimum fan speed is set pretty high. We think it should be closer to 500 RPM. Under higher loads and increased operating temperatures, the fan makes a lot more noise. Beyond 70% of the CX750M's maximum rated capacity, its fan is downright loud.

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.