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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.

  • Bit early for a review,but just installed mine to replace my old one that was power surging.
    Very easy to install and only use the extra cables you need.
    Piece of mind knowing the 3 year warranty that comes with it.
    Reply
  • RCFProd
    Thanks for the review!
    Reply
  • turkey3_scratch
    Funny how it doesn't have OTP, when as a matter of fact, OTP was the very thing that saved the original CX750M's butt in Jonnyguru's testing; but the majority of people, rather than realizing that was a good safety measure, took it instead as "the CX750M can't do more than 650W" when in fact it was just Oklahomawolf's hot box. So maybe to avoid another mishap like this altogether they just removed OTP and cheered over the money savings at the same time?

    I don't care for this PSU too much anyway. It seems to be a power supply that likes to focus on good ripple (as every modern PSU does these days) and decent voltage regulation but falls short in nearly every other aspect. I don't see it being much of any improvement over the original CX750M, the whole purpose of was probably just to cut costs. I'd happily take 60mv of ripple on my 12V rail in turn for some better holdup time, a higher quality fan and perhaps caps (if those Suscons aren't the best), and OTP.
    Reply
  • jonnyguru
    It does have OTP. There's something wrong with Aris's unit and I'm going to investigate it.
    Reply
  • JackNaylorPE
    I keep reading posts referencing the new CXM series, but the conclusions section which most readers skip to seem to follow Mom's advice ... "if ya don't have anything good to say, don't say anything" ... anything negative is left out. If the CX750M is going to be competitive, it has to address the elephant in the room that is the EVGA 750 B2 that sells for $50.
    Reply
  • RCFProd
    18929743 said:
    I keep reading posts referencing the new CXM series

    Aren't those usually either the 450w, 550w and 650 watts? Those are different units compared to the 750 watts I think.

    18929743 said:
    If the CX750M is going to be competitive, it has to address the elephant in the room that is the EVGA 750 B2 that sells for $50.

    Plenty of better options for power supplies around CX750M's price range, must be said. Isn't the EVGA B2 750w 65 dollars?
    Reply
  • turkey3_scratch
    Ya B2 is well priced http://www.newegg.com/Product/Product.aspx?Item=N82E16817438028&cm_re=evga_750_b2%5c-_-17-438-028-_-Product
    Reply
  • JackNaylorPE
    The CX450M, CX550M and CX650M were redesigned last year and manufactured by CWT using a custom Corsair design, while the CX750M (and I think the 850 model) was based upon CWTs PUQ B patform. This latest revision seems to be even newer .. and even beyond that, it appears to have changed yet again after the review samples went out as noted in the article the newer 650M's use a "470uF bulk cap but use instead a 330uF one".

    Note that the CXM series is reported as the lowest quality Corsair PSU available in the US.... yet several VS models remain available thru US e-tailers. One thing I have always observed, specifically with regard to PSUs and coolers is that forum posters, even when referencing an article that says the reviewed item was a "good budget model" or "good for the money, tend to drop the words "budget" and "for the money" when recommending it. So while it may be a logical choice for a G3258 or GTX 1050 build w/ no overclocking, I don't quite understand why a Hyper 212 or a CX series PSU gets recommended for a 6700k / 1070 build especially where OP states an interest in overclocking the bejeezes out of everything.

    Here's the only reviews I have seen besides this one:
    http://www.tomshardware.com/reviews/corsair-cx650m-psu,4770.html
    http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=486


    18929767 said:

    Aren't those usually either the 450w, 550w and 650 watts? Those are different units compared to the 750 watts I think.

    Plenty of better options for power supplies around CX750M's price range, must be said. Isn't the EVGA B2 750w 65 dollars?

    NCIX almost always has it for $50 in conjunction w/ Corsair MIR and instant savings... sometimes others like newegg

    NCIX = $45 (Savings Code 97531-1714. SAVE $25.00 off our regular price of $89.99 Special price ends 11/30/2016 + Save $20.00 USD with manufacturer's mail-in rebate!)
    http://www.ncixus.com/products/?usaffiliateid=1000031504&sku=97531&promoid=1714

    newegg = $89.99 - $20 instant savings - $20.00 rebate card = $49.99
    http://www.newegg.com/Product/Product.aspx?Item=N82E16817438028
    Reply
  • powernod
    If i was short on budget i wouldn't hesitate to use Corsair's CX-M line of PSUs.
    Solid units for that kind of price.
    I don't expect to have Seasonic PRIME 750's performance with 80$ !!
    Reply
  • turkey3_scratch
    18930459 said:
    If i was short on budget i wouldn't hesitate to use Corsair's CX-M line of PSUs.
    Solid units for that kind of price.
    I don't expect to have Seasonic PRIME 750's performance with 80$ !!

    If I needed 750W and it was between the EVGA 750 B2 and the CX750M, I'd probably take the former.
    Reply