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Deepcool PQ850M Power Supply Review

The Deepcool PQ850M achieves decent performance and it is silent.

Deepcool PQ850M
(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.

Load regulation is perfect on the main three rails and acceptable at 5VSB, where it doesn't matter much as long as this rail keeps its voltages within the specified range by the ATX spec. 

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 longer than 17ms, but the power ok signal is lower than 16ms. 

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.

Inrush current is low with 115V but pretty high with 230V. A higher resistance NTC thermistor would help here. 

Leakage Current

In layman's terms, leakage current is the unwanted transfer of energy from one circuit to another. In power supplies, it is the current flowing from the primary side to the ground or the chassis, which in the majority of cases is connected to the ground. For measuring leakage current, we use a GW Instek GPT-9904 electrical safety tester instrument.

The leakage current test is conducted at 110% of the DUT's rated voltage input (so for a 230-240V device, we should conduct the test with 253-264V input). The maximum acceptable limit of a leakage current is 3.5 mA and it is defined by the IEC-60950-1 regulation, ensuring that the current is low and will not harm any person coming in contact with the power supply's chassis.

Deepcool PQ850M

(Image credit: Tom's Hardware)

Leakage current is higher than competing offerings, but still lower than the limit. 

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.

Test12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
10%5.242A1.983A1.982A0.982A85.0186.479%0<6.044.78°C0.937
12.098V5.042V3.33V5.095V98.30240.65°C115.12V
20%11.495A2.976A2.973A1.181A169.97289.733%0<6.045.01°C0.962
12.098V5.041V3.33V5.083V189.42140.34°C115.12V
30%18.096A3.472A3.468A1.381A254.9990.468%71516.841.52°C0.975
12.099V5.041V3.33V5.07V281.85746.39°C115.11V
40%24.703A3.969A3.964A1.582A340.09590.527%72016.941.73°C0.981
12.099V5.04V3.33V5.058V375.68346.87°C115.11V
50%30.957A4.962A4.956A1.784A425.07390.166%73117.242.11°C0.984
12.100V5.039V3.33V5.046V471.43647.68°C115.11V
60%37.171A5.957A5.948A1.988A509.5989.514%75918.442.51°C0.986
12.100V5.037V3.329V5.031V569.28748.62°C115.11V
70%43.451A6.951A6.94A2.192A594.90288.828%101526.243.06°C0.987
12.101V5.036V3.329V5.019V669.72450.13°C115.1V
80%49.733A7.947A7.931A2.298A679.73288.084%145636.343.87°C0.989
12.101V5.035V3.328V5.006V771.68351.96°C115.1V
90%56.410A8.445A8.412A2.402A765.1487.222%184342.244.68°C0.99
12.101V5.034V3.328V4.996V877.23354.26°C115.09V
100%62.823A8.943A8.924A3.016A849.95686.164%204845.545.98°C0.99
12.101V5.033V3.328V4.974V986.44255.77°C115.08V
110%69.104A9.939A10.003A3.021A934.50984.924%206045.846.85°C0.991
12.101V5.032V3.328V4.966V1100.41357.1°C115.08V
CL10.116A11.957A11.894A0A101.31384.291%73317.239.74°C0.948
12.097V5.036V3.337V5.102V120.19445.26°C115.12V
CL20.116A19.9A0A0A101.41883.613%47612.637.97°C0.949
12.098V5.026V3.328V5.108V121.29445.12°C115.12V
CL30.115A0A19.774A0A67.38477.732%43811.736.69°C0.934
12.097V5.04V3.337V5.106V86.6944.7°C115.12V
CL470.216A0A0A0A849.7886.773%205245.647.46°C0.99
12.103V5.034V3.32V5.058V979.31556.99°C115.08V

The PSU doesn't sweat at high operating temperatures, but its fan gets screaming loud. Moreover, efficiency takes a huge hit, so you better not push it so hard. 

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.

Test12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
20W1.228A0.496A0.496A0.195A20.00669.956%0<6.038.99°C0.826
12.098V5.04V3.328V5.119V28.59936.03°C115.12V
40W2.702A0.694A0.694A0.293A40.00680.44%0<6.041.27°C0.895
12.098V5.04V3.329V5.116V49.73537.69°C115.12V
60W4.178A0.893A0.892A0.391A60.00684.566%0<6.042.14°C0.921
12.098V5.041V3.329V5.112V70.95838.38°C115.12V
80W5.648A1.091A1.09A0.49A79.96886.79%0<6.044.05°C0.936
12.098V5.04V3.329V5.108V92.1440.01°C115.12V

The fan is not needed to spin under light loads, even under increased temperatures. 

2% or 10W Load Test

From July 2020, the ATX spec requires 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.

12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)PSU Noise (dB[A])Temps (In/Out)PF/AC Volts
1.248A0.214A0.214A0.053A17.16166.798%0<6.030.33°C0.814
12.095V5.04V3.33V5.123V25.69227.6°C115.11V

It would be nice to see over 70% efficiency with a 2% load. 

Efficiency & Power Factor

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 same goes for Power Factor.

With normal loads, the competition is ahead. With 20-80W loads, the PQ850M performs better. Finally, with a 2% load, it cannot reach 70% efficiency, which is not a problem for the EVGA 850 G6, which uses a more advanced version of the Focus platform.

5VSB Efficiency

Test #5VSBDC/AC (Watts)EfficiencyPF/AC Volts
10.1A0.513W74.635%0.107
5.125V0.687W115.11V
20.25A1.281W77.404%0.219
5.121V1.655W115.11V
30.55A2.813W78.395%0.334
5.114V3.588W115.11V
41A5.105W78.324%0.405
5.104V6.518W115.11V
51.5A7.64W78.283%0.442
5.093V9.759W115.11V
63A15.155W76.86%0.489
5.051V19.717W115.11V

We would like to see over 79% average efficiency at 5VSB. 

Power Consumption In Idle And Standby

Mode12V5V3.3V5VSBWattsPF/AC Volts
Idle12.095V5.041V3.33V5.127V7.7610.505
115.11V
Standby0.0430.007
115.11V

Vampire power is low.

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)

The fan speed profile pushes the small fan to its limits, under high operating conditions. 

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)

At normal operating temperatures, close to 30 degrees Celsius, the PSU is silent with up to 620W loads. It exceeds 30 dBA with more than 690W, and it enters the 35-40 dBA zone with more than 750W at 12V. All in all, this is not a noisy PSU. 

MORE: Best Power Supplies

MORE: How We Test Power Supplies

MORE: All Power Supply Content

Aris Mpitziopoulos
Aris Mpitziopoulos

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

  • Co BIY
    This category seems to show all the competitors neck-and-neck. Are they all using the SeaSonic Gold Platform ?

    I don't mind the grid pattern and perhaps it's excellent airflow allowed for less fan.

    I think it looks particularly sharp on the back.
    Reply
  • drajitsh
    It is not ideal to buy a PSU right now because we are in a transition phase from the previous ATX spec to the new one. I am likely going to be forced to buy 2 systems for my office. They will have integrated graphics to start with and will be upgraded to low end discrete graphics in 1-2 years. Does your recommendation still stand?
    Reply
  • Co BIY
    drajitsh said:
    It is not ideal to buy a PSU right now because we are in a transition phase from the previous ATX spec to the new one. I am likely going to be forced to buy 2 systems for my office. They will have integrated graphics to start with and will be upgraded to low end discrete graphics in 1-2 years. Does your recommendation still stand?

    I don't think low end cards will be requiring the new connectors in the short term. This is a necessity only for the high end cards with crazy peak power draws.

    The makers of the low end cards will also build them to match the likely customer , you and the other 500 million people running machines without the ATX3.0 PSU upgrades.

    Question: Why are PSU's built with fan grills ? None of the other fans in PCs have grills and PSU fans aren't bigger or faster . Also readily replaceable fans could be a great selling point because users want to mod.
    Reply
  • Tom Sunday
    The old story...eveyone wants a piece of the pie! Deepcool once dedicated exclusively for PC cooling now into PSU's as well. Next we have Seasonic making memory. I wish that companies would perfect theiroriginally intended product line and giving us those results, instead of just plastering their nane on products made by others. I have no respect for this as it is a quick fix to make more money and even having some people believe that they have a better product when this is absolutely not the case .
    Reply
  • Co BIY
    Tom Sunday said:
    The old story...eveyone wants a piece of the pie! Deepcool once dedicated exclusively for PC cooling now into PSU's as well. Next we have Seasonic making memory. I wish that companies would perfect their originally intended product line and giving us those results, instead of just plastering their nane on products made by others. I have no respect for this as it is a quick fix to make more money and even having some people believe that they have a better product when this is absolutely not the case .

    I agree with you if they just slap their "Premium" name and a few RGB's to something of below average quality and then throw it out there at a Premium price.

    In this case they started with a very solid platform, executed it competently and it delivers the goods quietly.

    This PSU doesn't seem like it's worth getting the pitchforks out for.
    Reply
  • Tom Sunday
    Co BIY said:
    This PSU doesn't seem like it's worth getting the pitchforks out for.

    Yes you are on the point as always! My other 'Deepcool' thought and great hope was that someday perhaps air-cooling products will equal the thermal performance of AIO’s. In part many users even with extensive experience sometimes have trouble installing AIO’s into their case. Of course for the time being the sheer profits (or in Asetek’s case the patent license fees to other manufacturers) by keeping on manufacturing AIO’s is much more profitable. Hence perhaps stifling the development or serious further $$$ investments into the ‘inventiveness’ of air-cooling. Amazing though the AIO Asetek patent, filed in November 2004 has never been significantly improved upon and just basically copied over and over again. Of course and just perhaps further CPU development in the years ahead may offer whereby no CPU cooling will ever be necessary. That would of course be the best of both worlds!
    Reply
  • Co BIY
    Tom Sunday said:
    Yes you are on the point as always!

    Thank You for the compliment!

    Tom Sunday said:
    My other 'Deepcool' thought and great hope was that someday perhaps air-cooling products will equal the thermal performance of AIO’s. In part many users even with extensive experience sometimes have trouble installing AIO’s into their case.

    I agree with you that the simplicity, reliability and cost advantages of air cooling justify continued development. Lenovo has an interesting offset stacked air cooler design on their new Threadripper workstations that I would like to see make it to the DIY market .


    Lenovo Thinkstation P620 Review (at Anandtech)
    Reply