DeepCool GamerStorm DQ-M V2L 850W Power Supply Review

The DeepCool GamerStorm DQ-M V2L 850W power supply offers good performance but it isn't as quiet as the competing offerings.

DeepCool GamerStorm DQ-M V2L 850W
(Image credit: © Tom's Hardware)

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Primary Rails And 5VSB Load Regulation

The following charts show the main rails' voltage values recorded between a range of 40W up to the PSU's maximum specified load, along with the deviation (in percent). Tight regulation is an important consideration every time we review a power supply because it facilitates constant voltage levels despite varying loads. Tight load regulation also, among other factors, improves the system’s stability, especially under overclocked conditions and, at the same time, it applies less stress to the DC-DC converters that many system components utilize.

Load regulation is tight on all rails but 5VSB, where it doesn't play a significant role. 

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Hold-Up Time

Put simply; hold-up time is the amount of time that the system can continue to run without shutting down or rebooting during a power interruption.

The hold-up time is much longer than what the ATX spec requires (17ms), and the power ok signal is accurate. 

Inrush Current

Inrush current, or switch-on surge, refers to the maximum, instantaneous input current drawn by an electrical device when it is first turned on. A large enough inrush current can cause circuit breakers and fuses to trip. It can also damage switches, relays, and bridge rectifiers. As a result, the lower the inrush current of a PSU right as it is turned on, the better.

The inrush current is low with 115V and quite high, but still not dangerously high, with 230V. 

10-110% Load Tests

These tests reveal the PSU's load regulation and efficiency levels under high ambient temperatures. They also show how the fan speed profile behaves under increased operating temperatures.

Swipe to scroll horizontally
Test # 12V 5V 3.3V 5VSB DC/AC (Watts) Efficiency Fan Speed (RPM) PSU Noise (dB[A]) Temps (In/Out) PF/AC Volts
1 5.241A 1.994A 2.019A 0.988A 84.958 87.286% 944 23.1 40.42°C 0.955
12.088V 5.017V 3.269V 5.063V 97.333 43.61°C 115.16V
2 11.502A 2.992A 3.031A 1.188A 170.022 90.424% 947 23.7 41.12°C 0.982
12.095V 5.014V 3.267V 5.052V 188.027 44.59°C 115.16V
3 18.106A 3.491A 3.538A 1.389A 255.026 91.236% 950 23.7 41.29°C 0.985
12.094V 5.013V 3.265V 5.040V 279.522 45.29°C 115.16V
4 24.713A 3.993A 4.044A 1.591A 340.033 91.196% 952 23.5 41.42°C 0.981
12.092V 5.011V 3.263V 5.028V 372.860 46.14°C 115.16V
5 30.963A 4.990A 5.061A 1.795A 424.910 90.790% 958 23.0 42.68°C 0.980
12.092V 5.010V 3.261V 5.015V 468.012 47.85°C 115.16V
6 37.181A 5.991A 6.075A 1.999A 509.443 90.246% 963 23.2 42.77°C 0.982
12.093V 5.009V 3.260V 5.002V 564.505 48.48°C 115.16V
7 43.467A 6.991A 7.090A 2.205A 594.758 89.460% 1167 29.0 43.70°C 0.984
12.093V 5.008V 3.258V 4.989V 664.828 50.71°C 115.15V
8 49.760A 7.993A 8.107A 2.410A 680.055 88.683% 1717 39.2 43.87°C 0.985
12.091V 5.006V 3.256V 4.978V 766.836 51.38°C 115.15V
9 56.451A 8.495A 8.605A 2.413A 764.923 87.968% 2348 51.2 44.88°C 0.987
12.089V 5.003V 3.253V 4.971V 869.546 52.88°C 115.14V
10 63.068A 8.998A 9.131A 2.519A 849.626 87.136% 2347 51.2 45.18°C 0.988
12.089V 5.002V 3.252V 4.960V 975.058 53.77°C 115.13V
11 70.085A 8.998A 9.133A 2.523A 934.365 86.284% 2349 51.3 45.91°C 0.988
12.088V 5.000V 3.251V 4.953V 1082.893 54.80°C 115.11V
CL1 0.100A 12.999A 12.997A 0.000A 108.862 83.409% 972 24.2 42.34°C 0.970
12.106V 5.018V 3.264V 5.072V 130.516 47.39°C 115.16V
CL2 70.499A 1.001A 1.0001A 1.000A 865.531 87.728% 2344 51.3 45.05°C 0.988
12.089V 5.005V 3.258V 5.000V 986.602 53.90°C 115.12V

The efficiency levels get a big hit under high operating temperatures, showing that the parts that CWT used are not highly tolerant to harsh operating conditions. The cooling fan also has to work at its maximum speed from test #9, to cope with the thermal load and keep as cool as possible the low-quality FETs.

20-80W Load Tests

In the following tests, we measure the PSU's efficiency at loads significantly lower than 10% of its maximum capacity (the lowest load the 80 PLUS standard measures). This is important for representing when a PC is idle with power-saving features turned on.

Swipe to scroll horizontally
Test # 12V 5V 3.3V 5VSB DC/AC (Watts) Efficiency Fan Speed (RPM) PSU Noise (dB[A]) PF/AC Volts
1 1.227A 0.498A 0.506A 0.197A 19.984 69.403% 934 21.8 0.756
12.084V 5.019V 3.272V 5.088V 28.794 115.15V
2 2.455A 0.997A 1.009A 0.394A 39.974 80.311% 938 22.2 0.887
12.085V 5.018V 3.271V 5.082V 49.774 115.14V
3 3.687A 1.495A 1.514A 0.591A 60.005 84.531% 938 22.2 0.930
12.084V 5.017V 3.270V 5.075V 70.986 115.15V
4 4.919A 1.995A 2.022A 0.789A 79.951 86.506% 945 23.1 0.955
12.067V 5.008V 3.265V 5.070V 92.422 115.12V

With 20W load, efficiency doesn't exceed 70%. In all other tests, it exceeds 80%, though. 

2% or 10W Load Test

Intel plans on raising the ante at efficiency levels under ultra-light loads. So from July 2020, the ATX spec will require 70% and higher efficiency with 115V input. The applied load is only 10W for PSUs with 500W and lower capacities, while for stronger units we dial 2% of their max-rated-capacity.

Swipe to scroll horizontally
Test # 12V 5V 3.3V 5VSB DC/AC (Watts) Efficiency Fan Speed (RPM) PSU Noise (dB[A]) PF/AC Volts
1 1.240A 0.233A 0.232A 0.044A 17.118 66.003% 859 20.5 0.726
12.071V 5.014V 3.270V 5.092V 25.935 115.17V

With 2% load, the 70% efficiency mark isn't reached, so this PSU cannot meet the newest ATX spec requirements. 

Efficiency

Next, we plotted a chart showing the PSU’s efficiency at low loads, and loads from 10 to 110% of its maximum-rated capacity. The higher a PSU’s efficiency, the less energy goes wasted, leading to a reduced carbon footprint and lower electricity bills.

The efficiency levels are at satisfactory levels, given the parts that this platform uses. 

5VSB Efficiency

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Test # 5VSB DC/AC (Watts) Efficiency PF/AC Volts
1 0.100A 0.509 77.356% 0.063
5.093V 0.658 115.17V
2 0.250A 1.272 80.303% 0.142
5.090V 1.584 115.17V
3 0.550A 2.795 81.582% 0.255
5.083V 3.426 115.17V
4 1.000A 5.073 79.589% 0.353
5.073V 6.374 115.17V
5 1.500A 7.592 79.431% 0.406
5.061V 9.558 115.17V
6 2.499A 12.595 77.351% 0.461
5.039V 16.283 115.17V

The 5VSB rail is highly efficient! 

Power Consumption In Idle And Standby

Swipe to scroll horizontally
Idle & Standby Power Consumption
Mode 12V 5V 3.3V 5VSB Watts PF/AC Volts
Idle 12.070V 5.009V 3.267V 5.094V 21.726 0.673
115.2V
Standby 0.044 0.004
115.2V

The vampire power levels are low, with both voltage inputs. 

Fan RPM, Delta Temperature, And Output Noise

All results are obtained between an ambient temperature of 37 to 47 degrees Celsius (98.6 to 116.6 degrees Fahrenheit).

(Image credit: Tom's Hardware)

(Image credit: Tom's Hardware)

Up to 500W, the fan spins at below 1000 RPM, but at higher loads, the fan speed profile gets wild. The low-quality FETs don't allow for a more relaxed speed profile, as it seems. 

The following results were obtained at 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit) ambient temperature.       

(Image credit: Tom's Hardware)

(Image credit: Tom's Hardware)

There is no passive operation, but this is not a problem since the fan isn't noisy, with loads up to around 550W. With higher loads, though, the fan quickly increases its speed, and the same goes for the output noise, which exceeds 40 dBA with >610W loads. In some cases, noise can go over 45 dBA, so if you plan to push this PSU hard, you should be prepared for noisy operation. 

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Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a contributing editor at Tom's Hardware, covering PSUs.