Hot Test Results

As we can see in the following tables, the NZXT C650 delivers great power quality. The maximum voltage ripple on the 12V line is 28 mV, an unimpressive figure nowadays, but less than a quarter of the ATX design guide's recommended 120 mV limit. Ripple on the secondary 3.3V/5V lines is considerably worse, reaching 28 mV on the 5V line with a recommended maximum at 50 mV. We can notice the same pattern on voltage regulation, with the 12V line very tightly regulated at 0.7% and the regulation on the secondary 3.3V/5V lines reaching slightly over 2%.

Main Output
Load (Watts) 130.6 W 326.19 W 486.33 W 647.57 W
Load (Percent) 20.09% 50.18% 74.82% 99.63%
  Amperes Volts Amperes Volts Amperes Volts Amperes Volts
3.3 V 1.78 3.33 4.45 3.33 6.67 3.29 8.89 3.27
5 V 1.78 5.05 4.45 5.01 6.67 5 8.89 4.97
12 V 9.6 12.05 24.01 12.04 36.01 11.97 48.02 11.96


Line Regulation
(20% to 100% load)
Voltage Ripple (mV)
20% Load 50% Load 75% Load 100% Load CL1
3.3V + 5V
3.3V 2% 10 16 20 22 12 24
5V 1.6% 12 16 22 28 14 24
12V 0.7% 16 20 22 28 30 20

Operation in high ambient temperatures does not affect the performance of the NZXT C650 considerably, regardless of the load. The average nominal load range (20%-100%) efficiency drops by 0.8% regardless of the input voltage, going down to an average of 89.8% (230 VAC) / 88.1% (115 VAC). There is very little change across the entire load range, suggesting that the components of the PSU are practically unaffected by the high ambient temperature. The component temperatures are high but not overly so.

As expected, the thermal control circuitry of the NZXT C650 correctly detects the high ambient temperature inside our hotbox and adjusts the fan’s speed accordingly. The NZXT C650 is not silent under these operating conditions, with the fan’s speed gradually increasing along with the load. Nevertheless, the sound pressure level tops out at just 50.2 dB(A), a figure significantly lower than what we would expect from a unit with a powerful 120 mm fan.

Cold Test Results Final Words & Conclusion


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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