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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: © Tom's Hardware)

To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units. 

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.

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Results 1-8: Load Regulation

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

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.

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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.

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Results 13-14: Inrush Current

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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.

Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
CL10.100A12.999A12.997A0.000A108.86283.409%972 24.242.34°C0.970
CL270.499A1.001A1.0001A1.000A865.53187.728%2344 51.345.05°C0.988

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.

Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])PF/AC Volts

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.

Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])PF/AC Volts

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


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.

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Results 15-18: Efficiency

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

5VSB Efficiency

Test #5VSBDC/AC (Watts)EfficiencyPF/AC Volts
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Results 19-20: 5VSB Efficiency

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The 5VSB rail is highly efficient! 

Power Consumption In Idle And Standby

Idle & Standby Power Consumption
Mode12V5V3.3V5VSBWattsPF/AC Volts
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Results 21-22: Vampire Power

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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
Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.