Deepcool DQ850-M-V2L 850 W PSU review

PSU - Power Supply Units 108 Page 8 of 9 Published by

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Stability Testing the PSU

 Stability Testing The PSU

You can check the 80 Plus measurements (taken with 115 V input voltage) here. During our tests, we monitor voltage fluctuations at different loads. We write down the lowest and highest values. You want as little fluctuations as possible. The ATX specification requires that the PSU stay within a 5% fluctuation limit. For example, each +12 Volt rail should remain at between 11.4 and 12.6 Volts. This means that the PSU is operating within ATX-defined specifications. You can find the thresholds in the table below:

Now the measurements for the Deepcool DQ850-M-V2L unit:


Voltage

Threshold

Minimum Voltage

Nominal Voltage

Maximum Voltage

+3.3 V

(±) 5%

+3.14 V

+3.3 V

+3.47 V

+5 V

(±) 5%

+4.75 V

+5 V

+5.25 V

+12 V

(±) 5%

+11.4 V

+12 V

+12.6 V


Results DC Output Load Regulation
Combined DC Load +3.3 V +5 V +12 V
85 W (10%) 3,33 5,05 12,11
212.5 W (25%) 3,33 5,06 12,08
425 W (50%) 3,31 5,03 12,01
637.5 W (75%) 3,32 4,98 11,99
850 W (100%) 3,30 4,97 11,97

All results remained safely within the specification and tolerance thresholds. As you can see, when in use the PSU stays consistent. Voltages are very stable even at 100% load, and very close to the ideal values as per the ATX specification.

Sound levels (dBA)

As always, for sound level measurement, we used the Voltcraft SL-100 dBA meter. The human auditory system has different sensitivities at different frequencies. This means that the perception of noise is not at all equal at every frequency. Noise with significant measured levels (in dB) at high or low frequencies will not be as annoying as it would be if its energy was concentrated in the middle frequencies. In other words, the measured noise levels in dB will not reflect the actual human perception of the loudness of the noise. That's why we measure the dBA level. A specific circuit is added to the sound level meter to correct its reading in regard to this concept. This reading is the noise level in dBA. The letter A is added to indicate the correction that was made in the measurement. Frequencies below 1 kHz and above 6 kHz are attenuated, whereas frequencies between 1 kHz and 6 kHz are amplified by the A-weighting. We measure the dBA 75 cm away from the product (the usual distance between you and a desktop computer). This is a rather subjective test. The lowest dBA level we can measure in this room without any equipment activated is roughly 30 dBA.

  • At ~10-60% (idle) load you can barely hear the fan, it remains virtually silent.
  • At ~ 70-80% it's becoming slightly audible

Below you can find the RPM behaviour of the PSU fan:   


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You need to remember that it’s a 120 mm fan inside. The PSU remains rather silent under normal load conditions. The sound shouldn’t be very noticeable in a system equipped with a CPU cooler, chassis fans, and a GPU (at least till let’s say an 80% load). 


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If it’s under 38 dBA, you most probably won’t hear it at all, unless you bring your ears very close to the power supply unit. So, the Deepcool PSU should be more than acceptable for most users even at ~80% load.

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