Corsair CX650M PSU Review

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. 

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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 measured hits the spot, while the power-good signal lasts for shorter than required. At least it drops before the rails go out of spec, providing accurate information to the motherboard. This is a huge deal since we've seen a number of PSUs (including some high-end ones) have problems providing accurate power-good information. 

Inrush Current

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

The inrush current with 115V is quite high, while with 230V it's normal for 650W unit.

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 0.1 A. 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 Speed
Fan Noise
Temps (In/Out)PF/AC Volts
13.566A1.984A2.003A0.980A64.7381.46%840 RPM
27.7 dB(A)
36.49°C0.972
12.109V5.028V3.293V5.078V79.4640.16°C115.1V
28.174A2.981A3.009A1.180A129.6987.07%840 RPM27.7 dB(A)37.38°C0.988
12.094V5.021V3.287V5.066V148.9541.38°C115.1V
313.145A3.488A3.530A1.383A194.8588.22%840 RPM27.7 dB(A)38.54°C0.994
12.078V5.018V3.283V5.055V220.8742.97°C115.2V
418.118A3.988A4.021A1.585A259.7388.43%840 RPM27.7 dB(A)39.47°C0.996
12.063V5.014V3.279V5.042V293.7045.20°C115.1V
522.765A4.986A5.034A1.785A324.7088.16%840 RPM27.7 dB(A)41.90°C0.997
12.047V5.010V3.276V5.029V368.3349.23°C115.1V
627.419A5.994A6.050A1.990A389.7087.26%1200 RPM36.1 dB(A)42.17°C0.996
12.033V5.005V3.271V5.016V446.6250.26°C115.1V
732.083A7.007A7.069A2.195A454.6586.41%1430 RPM37.0 dB(A)43.12°C0.997
12.017V5.000V3.267V5.002V526.1551.50°C115.1V
836.768A8.010A8.091A2.404A519.6485.43%1685 RPM39.5 dB(A)43.70°C0.997
12.001V4.994V3.262V4.988V608.2652.42°C115.1V
941.889A8.516A8.624A2.405A584.5984.47%1950 RPM42.2 dB(A)44.31°C0.997
11.985V4.989V3.257V4.980V692.1053.27°C115.1V
1046.773A9.033A9.127A3.020A649.5383.30%2240 RPM45.5 dB(A)45.03°C0.998
11.969V4.985V3.253V4.963V779.7154.31°C115.1V
1152.278A9.040A9.134A3.025A714.5882.50%2240 RPM45.5 dB(A)45.22°C0.998
11.953V4.981V3.250V4.954V866.1954.88°C115.1V
CL10.100A16.024A16.004A0.003A133.5081.94%840 RPM27.7 dB(A)41.64°C0.990
12.092V4.997V3.262V5.056V162.9248.92°C115.1V
CL253.963A1.002A1.003A1.001A659.2483.98%2240 RPM45.5 dB(A)44.28°C0.998
11.970V5.003V3.273V5.006V785.0053.21°C115.1V

For such an affordable PSU, load regulation is pretty tight! All major rails are within 1.5%, with only 5VSB exceeding 2%. The CX650M surprises us in a good way by performing much better than we were expecting. When it comes to efficiency, the CX650M easily meets the fairly loose 80 PLUS Bronze requirements, although under higher loads efficiency takes a large hit. The synchronous design on the secondary side and the DC-DC converters that generate the minor rails surely play a large role in this.

Besides good performance, the CX650M also manages to offer quiet operation (even under high operating temperatures), so long as the applied load doesn't exceed 50% of its max-rated capacity. The only downside is that Corsair's minimum fan speed is quite high at 840 RPM. It could easily be lower than 600 RPM. In any case, output noise only exceeds 40 dB(A) with 90% and higher loads.

This thread is closed for comments
44 comments
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  • Dark Lord of Tech
    Thanks for the review on this new CXM platform.
  • JQB45
    Looks to be better then the old CX line up.
  • Onus
    Good to see that Corsair didn't produce a[nother] Turkey with this one.
  • turkey3_scratch
    Onus why would Corsair produce me?

    Anyway I think the price/performance page shows all. This thing rocks!

    Also Jonnyguru claims it is a rifle bearing fan that has the same model # as the sleeve variant.
  • benedict78
    Does the CX650 perform the same as the CX650M? I'm not interested in modularity anyway.
  • turkey3_scratch
    The CX650 is not out yet.
  • Aris_Mp
    I have several CM and CX-M units, which I plan to fully evaluate. So far I figured that there are differences (something natural of course) in their performance.
  • Dark Lord of Tech
    Could you put the newer CXM 750W OR 850W on deck soon , as they are widely use for DUAL CARD configurations.
  • turkey3_scratch
    The 750W and 850W CXM units are basically unchanged except for a bridge rectifier upgrade. Everything else is the same. Only the CX450-650M got the major revisions.
  • Dark Lord of Tech
    Yeah I know that , but want to see one reviewed , to compare top older generations.
  • Ryan_78
    Seems cool to be a CX now. Nice
  • bettsar
    After getting such high marks from the review, why no award?
  • Aris_Mp
    The CX750M is on the test bench right now. I don't have a CX850M sample.
  • Aris_Mp
    About the award. It should have a recommendation award but as it seems we forgot to add it. On it right now :)
  • Math Geek
    good to see them making a strong performer in a moderate price range. if they drop some massive rebates over the holidays like they do most years, this will be a super buy. i'm keeping my eye out to stock up on some. looks like a very solid buy.
  • atljsf
    the modularity is nice if you have a mini itx case, i have a cx500 and some of the unused cables are a bit inconvenient so that cx650m should be nice for those with not that small mini itx cases that can fit normal size psus
  • HERETIC-1
    Corsair spend $3 more and get all Jap capacitors and you'll have a good PSU.
    Oh you have-It's called the Vengeance series.(RECOMMENDED)
  • turkey3_scratch
    HERETIC you are severely misled. Do you realize there are Chinese capacitors of higher quality than Japanese? Do you realize how much ripple a capacitors handles and the environment the capacitors is in also affects it's lifespan a lot?

    Look at the thermal shots. The PSU is significantly cooler than was expected. That is fantastic for capacitor life. If you want to persist at judging power supplies based on capacitors country (and BTW a lot of Jap caps are outsourced to China) then you will be misled.
  • HERETIC-1
    So turkey are you saying Corsair's marketing "105C JAPANESE CAPACITORS"
    on their vengeance series is not necessary?
    I am more than happy to pay a little more when I see-
    "All electrolytic caps come from Nippon Chemi-Con"
  • turkey3_scratch
    The Vengeance series is a higher end unit than the CXM at a different price category for different countries. Not really fair to compare them.

    What more.could you possibly want at the price this thing sells for? This is the best value period and you have to find the need to talk about Japanese caps without even knowing the spec sheets of these caps used.
  • 10tacle
    "Finally, the number of provided cables and connectors is sufficient for this unit's capacity. And although it isn't fully modular, the native cables are absolutely necessary anyway."

    I've never understood the logic behind a "fully" modular PSU where all cables are completely disconnected and need to be plugged in. How exactly are you not going to use a PSU in a PC without the 20+4 pin ATX and 8 pin 12v CPU power connectors going to the motherboard?

    If anything, I'd want those connected directly during manufacturing to ensure nothing is lost (output or resistance) through a transfer connector port to the two most crucial power connectors.
  • atljsf
    202972 said:
    "Finally, the number of provided cables and connectors is sufficient for this unit's capacity. And although it isn't fully modular, the native cables are absolutely necessary anyway." I've never understood the logic behind a "fully" modular PSU where all cables are completely disconnected and need to be plugged in. How exactly are you not going to use a PSU in a PC without the 20+4 pin ATX and 8 pin 12v CPU power connectors going to the motherboard? If anything, I'd want those connected directly during manufacturing to ensure nothing is lost (output or resistance) through a transfer connector port to the two most crucial power connectors.


    the idea is that if you want a longer, half meter or a shorter, 15 centimeters long cable, you can change the one that came with the psu and put the one you need

    this is what most pc builders need this days, especially with mini itx cases where space is extremely limited
  • JQB45
    2011305 said:
    the idea is that if you want a longer, half meter or a shorter, 15 centimeters long cable, you can change the one that came with the psu and put the one you need this is what most pc builders need this days, especially with mini itx cases where space is extremely limited


    So If I buy power supply "A" for my mITX build and its fully modular but the cables are to long, where do I go to get shorter cables?
  • turkey3_scratch
    Cables cost like $100.