Corsair CX650F RGB Power Supply Review

The Corsair CX650F features RGB lighting which can be controlled either manually or through software.

Corsair CX650F RGB Power Supply
(Image: © Tom's Hardware)

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Primary Rails And 5VSB Load Regulation

The following charts show the main rails' voltage values recorded between a range of 40W up to the PSU's maximum specified load, along with the deviation (in percent). Tight regulation is an important consideration every time we review a power supply because it facilitates constant voltage levels despite varying loads. Tight load regulation also, among other factors, improves the system’s stability, especially under overclocked conditions and, at the same time, it applies less stress to the DC-DC converters that many system components utilize.

Load regulation is not that tight. We would like to see close or even better, below 1% at 12V. 

Hold-Up Time

Put simply; hold-up time is the amount of time that the system can continue to run without shutting down or rebooting during a power interruption.

The hold-up time is close to 17ms and the power-ok signal is accurate.

Inrush Current

Inrush current, or switch-on surge, refers to the maximum, instantaneous input current drawn by an electrical device when it is first turned on. A large enough inrush current can cause circuit breakers and fuses to trip. It can also damage switches, relays, and bridge rectifiers. As a result, the lower the inrush current of a PSU right as it is turned on, the better.

The inrush current with both 115V and 230V input remains at low levels. 

Leakage Current

In layman's terms, leakage current is the unwanted transfer of energy from one circuit to another. In power supplies, it is the current flowing from the primary side to the ground or the chassis, which in the majority of cases is connected to the ground. For measuring leakage current, we use a GW Instek GPT-9904 electrical safety tester instrument.

The leakage current test is conducted at 110% of the DUT's rated voltage input (so for a 230-240V device, we should conduct the test with 253-264V input). The maximum acceptable limit of a leakage current is 3.5 mA and it is defined by the IEC-60950-1 regulation, ensuring that the current is low and will not harm any person coming in contact with the power supply's chassis.

(Image credit: Tom's Hardware)

The leakage current is at very low levels. 

10-110% Load Tests

These tests reveal the PSU's load regulation and efficiency levels under high ambient temperatures. They also show how the fan speed profile behaves under increased operating temperatures.

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
13.564A1.974A1.987A0.999A64.96383.454%70915.9 40.90�C0.972
12.165V5.068V3.323V5.005V77.843 45.65�C115.11V
28.160A2.969A2.988A1.202A130.03088.029%74918.7 40.94�C0.976
12.147V5.053V3.316V4.992V147.713 46.60�C115.15V
313.108A3.472A3.489A1.406A195.03589.334%78820.6 41.30�C0.975
12.128V5.043V3.310V4.981V218.322 47.47�C115.12V
418.074A3.975A3.996A1.610A260.04589.638%84424.3 41.95�C0.983
12.108V5.032V3.304V4.969V290.105 48.96�C115.15V
522.713A4.984A5.005A1.816A325.08389.355%90025.4 42.82�C0.987
12.089V5.017V3.297V4.956V363.812 50.64�C115.15V
627.319A6.001A6.022A2.001A389.47088.768%98928.4 42.92�C0.988
12.071V5.000V3.289V4.943V438.750 51.97�C115.16V
732.011A7.024A7.041A2.232A454.92187.913%109431.7 43.71�C0.989
12.052V4.985V3.282V4.929V517.469 53.52�C115.13V
836.716A8.002A8.065A2.441A519.96286.978%124336.9 44.07�C0.991
12.033V4.968V3.274V4.916V597.810 54.46�C115.12V
941.836A8.578A8.569A2.445A585.13686.005%141239.5 44.76�C0.992
12.014V4.956V3.268V4.909V680.350 56.22�C115.11V
1046.711A9.102A9.105A3.071A649.96684.905%157142.0 45.15�C0.993
11.994V4.945V3.262V4.886V765.518 57.38�C115.12V
1152.207A9.115A9.118A3.074A714.79183.779%173644.3 46.54�C0.994
11.973V4.939V3.257V4.880V853.183 59.46�C115.11V
CL10.117A16.002A16.001A0.000A132.57381.892%1155 34.8 42.94�C0.970
12.163V4.916V3.280V4.986V161.887 51.61�C115.15V
CL254.015A1.000A1.000A1.000A660.70585.542%1499 41.8 45.29�C0.993
11.986V5.031V3.288V4.963V772.378 57.52�C115.10V

The PSU can handle tough conditions without any problems. We applied full load and overload for prolonged periods at high operating temperatures, and we didn't encounter any issues. 

20-80W Load Tests

In the following tests, we measure the PSU's efficiency at loads significantly lower than 10% of its maximum capacity (the lowest load the 80 PLUS standard measures). This is important for representing when a PC is idle with power-saving features turned on.

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])PF/AC Volts

Efficiency with 20W load is not so high, and we would like to see over 80% efficiency with 40W load. Nonetheless, this is a lower-efficiency category, so we shouldn't have high expectations.

2% or 10W Load Test

Intel plans on raising the ante at efficiency levels under ultra-light loads. So from July 2020, the ATX spec will require 70% and higher efficiency with 115V input. The applied load is only 10W for PSUs with 500W and lower capacities, while for stronger units, we dial 2% of their max-rated-capacity.

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])PF/AC Volts

Over 60% efficiency with 2% load, but not even close to 70%, as expected. 

Efficiency & Power Factor

Next, we plotted a chart showing the PSU’s efficiency at low loads, and loads from 10 to 110% of its maximum rated capacity. The higher a PSU’s efficiency, the less energy goes wasted, leading to a reduced carbon footprint and lower electricity bills. The same goes for Power Factor.

For the standards of this category, the CX650F fares very well. 

5VSB Efficiency

Swipe to scroll horizontally
Test #5VSBDC/AC (Watts)EfficiencyPF/AC Volts

The 5VSB rail has satisfactory efficiency. 

Power Consumption In Idle And Standby

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Mode12V5V3.3V5VSBWattsPF/AC Volts

Vampire power is kept low, with both voltage inputs (115V and 230V).

Fan RPM, Delta Temperature, And Output Noise

All results are obtained between an ambient temperature of 37 to 46 degrees Celsius (98.6 to 114.8 degrees Fahrenheit).

(Image credit: Tom's Hardware)

(Image credit: Tom's Hardware)

The fan speed curve increases linearly as the load increases, even under high operating temperatures. 

The following results were obtained at 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit) ambient temperature.       

(Image credit: Tom's Hardware)

(Image credit: Tom's Hardware)

The PSU reaches 30 dBA once the load exceeds 370W. With higher than 490W load, you will be treated to over 35 dBA noise output from the unit's fan. Given the platform's good efficiency levels, the fan speed profile could be a bit more relaxed under normal temperatures. Nonetheless, the Teapo SC caps, along with the five-year warranty, most likely didn't leave much room for lower fan speeds.

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Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.

  • mdd1963
    LEDs....! (Thank goodness!) <rolls eyes sarcastically>
  • derekullo
    If you use 2 Geforce 3090s the power supply changes to another color.

  • Cata1yst
    Is this a joke?