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


View All Comments

  • MrVibrato - Wednesday, August 12, 2020 - link

    That's what makes a trained eye: To know where to look (: Reply
  • NeatOman - Wednesday, August 12, 2020 - link

    Would have liked to see ripple measurements and at different loads Reply
  • jonnyGURU - Friday, August 14, 2020 - link

    Hey guys! This PSU is designed to last while all other PSUs are not!!!! What kind of bullshit marketing is that? Reply
  • Alien88 - Sunday, August 16, 2020 - link

    Why are there almost no regular power supplies below 500W or so nowadays? A typical home PC build using an APU and SSD is never going to draw more than around 150W, yet unless you buy a flex ATX or similar PS, you are stuck using a massively overpowered PS that will have shit efficiency at typical operating powers of a regular PC. It seems that virtually all ATX PSs are aimed at the gaming market. For those who neither want nor need a separate GPU, there are very few viable choices. The sad thing is, most people buy a PC with a ridiculously overpowered graphics card simply because they might need it one day, or they simply don't know any better and think they actually need one. Vega graphics has proven that to be untrue (I have a 2400GE and yet do DTP and other graphical design and editing stuff for magazines etc without issue). Imagine how much energy is being wasted globally because of poor hardware choices and a lack of options from manufacturers. Reply
  • 80-wattHamster - Monday, August 17, 2020 - link

    Cuz it costs about the same to make a 500W power supply as a 350, and you can charge more for it.

    Funny thing is, even when you find a decent 350-ish unit, it'll probably cost more than you'd pay for a 500+ because volumes and channels and other such malarkey. Frustrating.
  • Threska - Monday, August 31, 2020 - link

    Lesson number one. Two components to never cheapen out on. First is PSU, and the other is motherboard. Most intermittent problems people have can be traced to those two. It may cost more, but it may go through several rebuilds as well. Reply
  • Threska - Monday, August 31, 2020 - link

    Well I'm a gamer with a Vega, and occasionally I can see the struggles with the latest games. So, no, "overpowered" is a moving target, especially in a seven year time-frame. Reply

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