Cold Test Results

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M  40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.

From the above charts, we can see that the NZXT C650 meets the 80Plus Gold certification requirements when powered from either a 230 VAC or 115 VAC outlet, even if only barely. It almost missed the certification requirements at 20% load and we can see that the efficiency of the PSU plummets as the load decreases, dropping well below 70% when the load is lower than 35 Watts. When the load drops below 20%, the efficiency drops so much that the raw power losses increase – a very rare effect. Apparently, this platform is not designed to cope with loads much lower than those intended.

We tested the NZXT C650 with its hybrid fan mode disabled, meaning that the fan was running at all times. In that scenario, the fan only became noticeable when the load ws greater than 320 Watts, and remained barely audible for loads up to 450 Watts. It eventually reached 42.9 dB(A) under maximum load, a passable noise figure for most users, and a great result from a PSU that is using a 120 mm fan. Considering that a PSU should never run at maximum load for prolonged periods of time, the NZXT C650 should be unnoticeable if installed inside a well-ventilated case.

Introduction, Examining Inside & Out Hot Test Results
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  • eek2121 - Tuesday, August 11, 2020 - link

    I accidentally bought a Seasonic PSU thanks to Amazon’s infuriating inability to do a proper search. Still trying to decide whether to keep it or return it. Reply
  • evilspoons - Tuesday, August 11, 2020 - link

    Small nitpick on the "Main Output" table on the Hot Test Results page. At 20% you read 5.05 V, at 50% you read 5.01 V, and at 100% you read 4.97 V. All two decimals of precision. However, at 75% load it's just listed as "5 V". Shouldn't that be "5.00"? Reply
  • fred666 - Tuesday, August 11, 2020 - link

    What's the point of being 100% modular? Is someone really going to use this without the main ATX motherboard connection?
    It looks nice in the box, but I don't see any real-world advantage.
    Reply
  • eek2121 - Tuesday, August 11, 2020 - link

    The cables can easily be replaced. For example, cablemod allows you to purchase custom length cables. Also, what if a connector or cable breaks? Reply
  • Threska - Monday, August 31, 2020 - link

    I could see someone going with a shorter ATX power connector. Especially since in my case it really is a short distance and most cables are really long. Reply
  • plonk420 - Tuesday, August 11, 2020 - link

    less clutter in your case if you don't have very many components. my daily driver is a 2400G + m.2 ...and 3 SATA devices Reply
  • Lord of the Bored - Wednesday, August 12, 2020 - link

    That doesn't explain why you'd want to remove the main ATX power connector.
    I grant that there ARE some situations where you don't want the motherboard power connector, but they are very rare and the people that need them are used to "manually reconfiguring" the power supply already.
    Reply
  • GreenReaper - Wednesday, August 12, 2020 - link

    You may, however, wish to replace it if the cable has been frayed somehow, or a connector broke.

    Might not happen for most people, but you'll be (relatively) glad if it does for you.
    Reply
  • Arbie - Tuesday, August 11, 2020 - link

    Very important info missing from your cables chart is their lengths. At least, this becomes very important if one neglects to check it... Reply
  • Stele - Wednesday, August 12, 2020 - link

    "A trained eye will easily identify the OEM behind the NZXT C650 to be Seasonic" Ya know, it does expressly say right on the PSU label that Seasonic is the OEM... Reply

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