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)

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Advanced Transient Response Tests

For details about our transient response testing, please click here.

In the real world, power supplies are always working with loads that change. It's of immense importance, then, for the PSU to keep its rails within the ATX specification's defined ranges. The smaller the deviations, the more stable your PC will be with less stress applied to its components. 

We should note that the ATX spec requires capacitive loading during the transient rests, but in our methodology, we also choose to apply a worst case scenario with no additional capacitance on the rails. 

Advanced Transient Response at 20% – 20ms

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Advanced Transient Response at 20% – 10ms

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Advanced Transient Response at 20% – 1ms

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Advanced Transient Response at 50% – 20ms

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Advanced Transient Response at 50% – 10ms

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Advanced Transient Response at 50% – 1ms

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Only 5V and 5VSB perform well in these tests. The +12V is away from 1% deviation, which is considered good performance while the deviation at 3.3V exceeds 4%. 

Turn-On Transient Tests

In the next set of tests, we measure the PSU's response in simpler transient load scenarios—during its power-on phase. Ideally, we don't want to see any voltage overshoots or spikes since those put a lot of stress on the DC-DC converters of installed components.

We only noticed a small spike at 5VSB and two small steps during the last test. All in all, good enough performance here. 

Power Supply Timing Tests

There are several signals generated by the power supply, which need to be within specified, by the ATX spec, ranges. If they are not, there can be compatibility issues with other system parts, especially mainboards. From year 2020, the PSU's Power-on time (T1) has to be lower than 150ms and the PWR_OK delay (T3) from 100 to 150ms, to be compatible with the Alternative Sleep Mode.

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PSU Timings Table
T1 (Power-on time) & T3 (PWR_OK delay)

The PWR_OK delay is out of the 100-150ms region, so the PSU does not support the alternative sleep mode (ASM). No mainboards are supporting this mode yet, but given the ten-year warranty, you will keep this PSU for quite long, so it would be ideal for supporting ASM.

Ripple Measurements

Ripple represent the AC fluctuations (periodic) and noise (random) found in the PSU's DC rails. This phenomenon significantly decreases the capacitors' lifespan because it causes them to run hotter. A 10-degree Celsius increase can cut into a cap's useful life by 50%. Ripple also plays an important role in overall system stability, especially when overclocking is involved.

The ripple limits, according to the ATX specification, are 120mV (+12V) and 50mV (5V, 3.3V, and 5VSB).

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10% Load25.6 mV7.7 mV6.3 mV8.2 mVPass
20% Load16.3 mV8.9 mV6.4 mV11.9 mVPass
30% Load17.9 mV15.5 mV6.7 mV15.9 mVPass
40% Load18.6 mV20.0 mV7.5 mV18.4 mVPass
50% Load14.0 mV15.0 mV7.6 mV24.0 mVPass
60% Load11.3 mV15.1 mV8.0 mV22.6 mVPass
70% Load10.2 mV17.8 mV8.9 mV15.9 mVPass
80% Load10.6 mV18.2 mV11.3 mV17.4 mVPass
90% Load11.5 mV18.0 mV11.6 mV19.0 mVPass
100% Load18.0 mV19.4 mV13.1 mV19.3 mVPass
110% Load19.6 mV19.3 mV13.4 mV19.6 mVPass
Crossload 123.4 mV15.0 mV12.4 mV5.5 mVPass
Crossload 217.2 mV16.9 mV9.6 mV22.4 mVPass

The ripple suppression is good on all rails, even at 5V, which looks high in the charts compared to other, similar spec, PSUs. From the moment the minor rails stay below 20mV, at full load and higher than 45 degrees Celsius ambient, we cannot complain about their performance. 

Ripple At Full Load

Ripple At 110% Load

Ripple At Cross-Load 1

Ripple At Cross-Load 2

EMC Pre-Compliance Testing – Average & Quasi-Peak EMI Detector Results

Electromagnetic Compatibility (EMC) is the ability of a device to operate properly in its environment without disrupting the proper operation of other nearby devices.

Electromagnetic Interference (EMI) stands for the electromagnetic energy a device emits, and it can cause problems in other nearby devices if too high. For example, it can be the cause of increased static noise in your headphones or/and speakers.

(Image credit: Tom's Hardware)

With the Average detector several, sixteen to be exact, spurs exceed the limits in the 342 - 808 kHz range. Using the QP detector, which is more accurate, everything is ok, although some emissions are dead close to the limits. 

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Contributing Editor

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