Deepcool DQ750 Quanta Semi-Modular Power Supply Review

by - 6 years ago


Introduction & Packaging

Deepcool_DQ750 (10)

Deepcool have been making their presence felt in the PC DIY market increasingly more over the last year. They have made a push towards gaming and enthusiast market segments with new cooling solutions, cases and power supplies. Today we have one of Deepcool’s newest power supplies on the test bench: the Deepcool DQ750. As its name suggests, this is a 750 watt power supply and it is very much targeted at PC enthusiasts with 80 Plus Gold certification, a Blue LED fan and a modular design with flat black ribbon cables. Deepcool have opted for a semi-modular design but unlike some power supply vendors they have also ensured that the hard-wired cables conform to an all-black aesthetic just like the modular cables. Deepcool’s expansion into the power supply market for consumer buyers is certainly an interesting one and given that Deepcool have teamed up with Corsair’s preferred OEM Channel Well Technology we could see Deepcool competing for similar buyers with similar features. Let’s see what the DQ750 has to offer.


Packaging and Contents

Packaging is fairly simple for such a high-end unit; a gold colour scheme is used to reflect the unit’s efficiency certification. I’m not so sure about the “Enjoy Your Cool Life” slogan; it seems it was thrown together in just a few moments.

Deepcool_DQ750 (1)

Included with the DQ750 is a power chord, four black case screws and a warranty card. Note there is no manual provided, in physical form or online at the product page, which is a bit strange. Deepcool also do not provide any cable ties.

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A Closer Look – Exterior

Power Supply Unit

Deepcool use a textured industrial-looking black coating for the DQ750. It certainly gives the unit a unique look and feel and makes a change from the normal plain black metal. The fan is a rather large 140mm unit with Blue LEDs, it comes with a nice gold-coloured fan grille featuring a Deepcool logo at the centre.

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At the cable end of the power supply we find all of the modular connectors and the pre-fitted cables. Deepcool’s labelling of what holes are for what cables could be clearer, but it’s quite obvious: red for PCIe and black for everything else.

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On both sides there are stickers; one side gets the specifications of the unit while the other side just has some branding.

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Deepcool_DQ750 (11)

The base is totally plain as is becoming increasingly common with a lot of power supplies.

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At the rear there is abundant hexgonal mesh for airflow, a kettle lead input and a simple power switch.

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Deepcool provide 24 pin motherboard and 4+4 pin CPU connectors pre-fitted, everything else is modular.

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Four PCIe 6+2 pins, 6 SATAs and 6 Molex make up the rest of the connectors. There’s no FDD connector so if you still use an FDD power for something you’ll need to buy a separate adapter for that.

Deepcool_DQ750 (3)


A Closer Look – Interior

The OEM producer for Deepcool’s first consumer power supply line is CWT; Channel Well Technology. CWT are known for making cost-effective platforms which explains why they’ve featured in so many power supply products of late.

Deepcool_DQ750 (5)

The capacitor used for the primary side is not the best available but CapXon 85 degrees celsius rated units are still good quality. This hold up capacitor provides 390uF at 400 volts.

Deepcool_DQ750 (6)

For the secondary side we find some more CapXon filtering capacitors as well as a few 105 degrees celsius rated capacitors. The quality of the capacitors used is good but there is certainly room for improvement if Deepcool wanted to make a more premium performing unit.

Deepcool_DQ750 (7)

Two Y capacitors handle initial line filtering at the AC receptacle, further filtering is done on the main PCB once the current is passed down.

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The provided fan is made by YateLoon and is a 140mm unit. It features a blue LED and has a maximum rotational speed of 2000 RPM.

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Test Procedure

At eTeknix we take the power supply testing procedure very seriously and have invested a lot of resources into acquiring the appropriate testing equipment. For all power supply reviews we test the power supplies with dedicated power supply testing equipment. This means we are able to get the most accurate results from our testing as opposed to using software benchmarks (such as OCCT) or multi-meter readouts which are broadly inaccurate.


Our test machinery is as follows:

  • Sunmoon SM-5500ATE Active Load Tester (1200W rated)
  • Stingray DS1M12 USB Oscilloscope
  • Voltcraft DT-10L laser tachometer

The eTeknix test procedure involves:

  • Testing each power supply at 20/40/60/80/100% load (with balanced load across all rails) and measuring PFC (power factor correction), efficiency (actual power divided by power “pulled at the wall”) and voltage regulation (deviance from expected voltages of 3.3/5/12 on the main rails).
  • Measuring ripple with an oscilloscope at 20/40/60/80/100% load.
  • Measuring fan speed after a stabilisation period of five minutes at each load scenario using the Voltcraft DT-10L laser tachometer and a reflective strip on the fan.
  • Testing each power supply’s OPP (Over Power Protection) mechanism and seeing how many watts each power supply can deliver before shutting down

Other things to consider are that

  • We recognise that a single yellow 12 volt cable can provide only 6 Amps before overheating (which corrupts voltage regulation and efficiency) and so we used an adequate number of cables for each power supply to ensure there is not efficiency loss from poor cables selection
  • Our Sunmoon SM-5500ATE power supply tester is not capable of testing more than 300W on each of the 12 volt rails so where a power supply provides more than 300W on a 12 volt rail that power is distributed over multiple 12 volt rails on the load tester. For example a power supply with one 12 volt rail supplying 750 watts would be spread equally over three 12 volt rails on the load tester, a power supply with two 450W 12v rails would be spread over four 12v rails on the load tester, two 225W 12v rails for each of the 12v rails on the unit.
  • We use the same time scale and horizontal millivolt scale on our oscilloscope for all ripple tests, that is a 20ms T/DIV (horizontal) and a 0.02 V/DIV (vertical) meaning the scale is from -80mV to +80mV, ATX spec dictates that the 12v rail must fall within 150mv of ripple and the 3.3/5 within 50mv so that scale allows us to include both 150 and 50mV peaks. (Some older PSU reviews use different scales which were later ditched as the visual representation they give is inadequate, in these reviews written measurements are provided only).
  • Deviance is the terminology used to represent the way voltages diverge from the expected values

Efficiency, PFC and Voltage Regulation

Voltage Regulation

To test voltage regulation we load the power supply to five different load scenarios that give an equal spread of load across every single rail. So that means 20% on all rails, 40% on all rails and so on. We then calculate the average deviance of each rail from its expected voltage.


Voltage regulation is strong on all major rails, within 1.25% which is a great result. Only the obsolete minus 12 volt rail suffered from poor performance, but this is easily overlooked.

Power Efficiency

Power efficiency is measured by calculating actual supplied wattage divided by the wattage drawn at the wall/plug, multiplied by 100 to give a percentage. We then compare that to the particular 80 Plus certification the company claims to see if it meets that. You can see the 80 Plus certifications below, we always test 230v power supplies.



80 Plus Gold is claimed and 80 Plus Gold is delivered almost to the exact specification required.

Power Factor Correction

Power Factor Correction is the ratio of the real power flowing to the load, to the apparent power in the circuit. The aim of PFC is to make the load circuitry that is power factor corrected appear purely resistive (apparent power equal to real power). In this case, the voltage and current are in phase and the reactive power consumption is zero. The closer the number to one the better as this allows the most efficient delivery of electrical power (Source – Wikipedia).


PFC starts off quite low and does recover from 60% but we’ve certainly seen much better in the past: the performance is fairly average.



Noise and Ripple can easily be measured by an oscilloscope. These show how much voltage fluctuation there is on a particular rail. We tested the rail stability of the 3.3 volt, 5 volt and 12 volt rails using an identical time and millivolt scale for all graphs. millivolt ripple is measured by the peak to peak size of the voltage curve.


Sample Ripple Graph

The latest ATX 12 volt version 2.3 specifications state that ripple from peak to peak must be no higher than 50 millivolts for the 3.3 volt and 5 volt rails, while the 12 volt rail is allowed up to 120 millivolts peak to peak to stay within specifications. Millivolt figures are stated to the closest increment of 5 given their variability.

Load (%) 3.3V Ripple 5V Ripple 12V Ripple
20  7  8.2  21.6
40  7.2  8.4  27.6
60  7.4  8.6  35.8
80  8.2  9.8  46.6
100  9.4  10.6  59.6

Ripple suppression is where this unit performs well, on the 3.3 and 5 volt rails exceptional ripple suppression can be seen which is testament to the quality of the secondary side construction. The 12 volt rail is also strong but nearing 60 mV isn’t the best we’ve seen; it is a strong result but premium units will tend to have sub 35 mV.

3.3 volt @ 100%


5 volt @ 100%


12 volt @ 100%



Over Power Protection and Max Wattage

Power supplies often quote as having various protection mechanisms such and the most important of these is Over Power Protection. In our testing we crank up the power draw until the power supply either shuts down (meaning the OPP mechanism is present and working) or blows up (meaning it is either not present or not working). We then note the maximum power consumption before the power supply shut down (or blew up).


The DQ750 just kept on going when we ran our OPP test, a staggering 1310W was delivered before the OPP mechanism triggered. This is an interesting result and makes me wonder if we’ll see Deepcool use the same platform as this to provide higher wattage models with only a few minor tweaks.


Fan Speed

When testing in a power supply laboratory it is difficult to take fan noise readings as the noise from the Sunmoon test equipment and air conditioning corrupts everything. The next best thing in our circumstances was reading off the fan speed with a tachometer to get an idea for the noise. The ambient temperature during testing held constant at 22 degrees, with 1 degree of variation. Each power supply had a consistent time period of 5 minutes to stabilise between each load scenario. 

In my experience the following general relationships apply between noise levels and fan speeds, though it can vary greatly between the type of fan used.

  • Below 800 RPM – Inaudible/Silent
  • 800 to 1000 RPM – Barely audible
  • 1000 – 1200 RPM – Audible but still quiet
  • 1200 – 1400 RPM – Moderately noisy
  • 1400 – 1800 RPM – Noisy
  • 1800 RPM or higher – Intolerable


Fan speed is strong thanks to the high quality Yate Loon fan used. Only at 100% is the PSU noticeably audible, sub 100% and we find the noise is very subdued and perfect for any silence loving PC user.


Final Thoughts


We cannot find Deepcool’s DQ750 power supply listed at any major retailers in the UK or the USA, a little strange but we assume the fact this product is quite new is the reason for this: it has yet to make a proper retail landing. Deepcool claim an MSRP of $129.99 on this unit but we’re not sure how this translates into actual retail pricing. At the sub $130 price point there is a huge array of 80 Plus Gold rated 750W units with better features or better pricing. Deepcool need to land this unit on the shelves at around $110 to stay competitive in my opinion. Deepcool offer a 3 year manufacturer’s warranty with this product.


The Deepcool DQ750 is a solid power supply unit. Our testing has revealed strong voltage regulation and efficiency are the main selling points of this unit. Ripple suppression is fantastic on the 3.3 and 5 volt rails but is less impressive on the 12 volt rail: especially given the price point of $130 that Deepcool occupy. The unit does have some nice features with all-black cables and an LED fan but there’s also a fair amount missing. There’s no fully modular design which is a negative for the price point and there’s also no LED switch to turn off the LEDs if you so desire. For the wattage it also feels like this unit is lacking in cables: more SATA connectors are needed and there’s no FDD option, both of which are needed to match rival offering.

With retail pricing and availability being so scarce it is difficult to come to a concrete conclusion about the Deepcool DQ750. If it arrives at $100-110 it would make a solid buy, but at $130 which is the only price we have to work with I feel that not enough is offered. There are too many rival units offering better connector selections, fully modular designs, hybrid fan modes and more: all things this unit doesn’t have. As I write this Corsair, SilverStone, Antec, Thermaltake, XFX, Seasonic and Rosewill all offer lower cost power supplies that do the same thing, if not slightly better. Deepcool’s entry into the power supply market is certainly a good start but I can see room for improvement.


  • Strong voltage regulation
  • Excellent 3.3 and 5 volt ripple suppression
  • High efficiency
  • Quiet operation
  • All black cables


  • Too costly
  • No LED on/off option
  • Not fully modular
  • Not enough SATA connectors and no FDD
  • No user manual online or in physical form

“The DQ750 is a solid starting point for Deepcool’s entry into the world of consumer power supplies. If Deepcool can get the pricing right this unit promises to be a strong contender in a highly competitive market segment.”

Thank you to Deepcool for providing this review sample.

Article Index

  1. Introduction and Packaging
  2. A Closer Look - Exterior
  3. A Closer Look - Interior
  4. Test Procedure
  5. Efficiency, PFC and Voltage Regulation
  6. Ripple Testing
  7. OPP and Max Wattage
  8. Fan Speed
  9. Final Thoughts
  10. View All

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Add a Comment

1 Comment on Deepcool DQ750 Quanta Semi-Modular Power Supply Review

  • Avatar Rio Amaterasu says:

    want an honest review on this one.. no BS no marketing all real.. coz
    i’m planning on buying one of these but since other rated this as
    “china made” i’m kinda having doubts.. Please reply anyone?

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