Overview of the Deepcool DQ750ST 750 W power supply / Overclockers.ua

Deepcool products are not a frequent guest on the pages of our site, although its popularity in the domestic market is growing from year to year. The latter is due to an affordable price with a good quality of Chinese brand solutions. We have already been testing cases and cooling systems of this brand, this time we will consider a power supply unit, a feature of which is compliance with the 80 Plus Gold certificate and, of course, an affordable price tag.

Deepсool DQ750ST

The power supply in question belongs to the DQ ST series introduced back in 2015, which complemented the Deepcool Quanta line of “gold” products. The main visible differences between the series are the size of the fan used, the lack of modular cabling in the DQ ST, and the available power outputs of the devices. The DQ750ST is the top of the range, with 550W and 650W units available, while the Quanta includes 850W, 1000W and 1250W solutions.

The device comes in a black box with gray edges, which lists the main features of the product in question, including the use of a quiet PWM fan, 120,000 hours MTBF, high-quality capacitors, and a 5-year warranty. The electrical parameters of the unit and the number of connectors are also indicated.

The DQ750ST is securely protected by an airbag, which is surprising for a device at this price point. But the package did not surprise at all – it contains only a network cable, a set of mounting screws and a warranty card.

The power cables are stationary, flat, but their number is not at all large:

• one to power the motherboard (43 cm);
• one with one 8-pin (4+4) CPU power connector (61 cm);
• two with two 8-pin (6+2) connectors for powering PCI-E video cards (46 cm);
• one with three power connectors for SATA devices and one for IDE (35+10+10+10 cm);
• one with two power connectors for IDE devices and two for SATA (34+10+10+10 cm).

The cables turned out to be depressingly short, this is especially true for cables for powering video cards. In some cases, it will be difficult to reach the motherboard. For peripheral devices, the wires also do not differ in particular length; when connecting, motley connectors will require a 180-degree turn of the cable, which is unlikely to bring an aesthetic component to the assembled system. But, fortunately, devices with a Molex connector are already extremely rare.

Externally, the device looks like many retail products: a black case and the same wire grill protecting the fan. A similar design we previously met with Gigabyte GP-B700H.

As for the characteristics, the Deepcool DQ750ST has one + 12V line with the ability to power the load up to 744 watts. The combined power of the low-voltage channels is 120 W, which is enough for a modern system.

For the standby voltage and the -12V line, 2.5 and 0.3 amperes are provided, respectively.

Active PFC and the ability to work in a wide range of mains voltage are declared. Of the protections are present: from low and high voltage, from short circuit and overload of the output lines. There is an automatic fan speed control.

The block itself is built on the “gold” CWT platform, which is found, for example, in the solutions of Cheftec, Enermax and the same Gigabyte. The circuitry is already standard for such products – a resonant converter in the high-voltage part and a synchronous rectifier in the low-voltage part. Independent stabilization of output voltages is based on DC/DC converters.

The number of parts is small, it seems even less than in some “bronze” solutions. The block is assembled well, some components are additionally glued with sealant.

Despite the apparent simplicity of the device, the input filter is made with all the necessary components, including a varistor and a relay with a thermistor.

To cool the elements of the input circuit, a common aluminum radiator is used, which extends along the entire board. The synchronous rectifier transistors are located on the reverse side of the PCB and are additionally cooled by thin light alloy plates.

The resonant converter and synchronous rectifier are based on the CM6901X controller, located on a small scarf near the inner wall of the power supply. The APFC module is controlled by the CM6502 chip soldered on the back side of the main PCB.

The converter for low-voltage channels is implemented on a separate board due to the APW7159 PWM controller, and the Sitronix ST9S313-DAG chip is responsible for monitoring.

The input circuit is equipped with a 470 uF capacitance with an operating temperature of 85 ° C Taiwanese Elite, the rest of the “high-quality” capacitors are limited to the Chinese-Taiwan brands CapXon, JunFu and ChengX. There are also polymer containers.

There are no special complaints about the quality of soldering, everything is done at the proper level and there is simply nothing to complain about.

The DQ750ST is cooled by a proprietary 120mm DF1202512CH-003 fan with a fluid dynamic bearing and “dual-layer” blades designed to reduce noise. Belongs to the GamerStorm series, has a two-pin connection and its maximum rotation speed is 1800 rpm.

When the system is idle and under light load, it rotates at a speed of 700 rpm, which increases to 1340 rpm with increasing power consumption. It works in this mode really quietly, no parasitic overtones are observed, only the rustle of air. When the block was overloaded, the speed increased to 1750 rpm, the noise, of course, already made itself felt.

The only nuance that you might not like about this fan is the imperfect casting of the impeller – various burrs were observed along all edges, and without them, most likely, this model would have worked even quieter.

Test Methodology

It is difficult to carry out full testing without an appropriate stand, so the power supplies were tested using a conventional system assembled from the following components:

• processor: Intel Core i7-6700K (4.0@4.5 GHz);
• motherboard: ASUS Maximus VIII Formula (Intel Z170);
• Cooler: Prolimatech Megahalems;
• RAM: HyperX HX430C15PB3K2/16 (2×8 GB, DDR4-3000, 15-16-16-35-1T);
• video cards: GeForce GTX 1080;
• drive: Kingston SSDNow UV400 240GB (240 GB, SATA 6Gb/s).

Testing was carried out in the Windows 10 x64 environment on an open stand. The Valley benchmark was used to create a game load on the system, and LinX 0.6.7 was launched in parallel for additional load.

Also, for maximum load, the following system was assembled:

• processor: Intel Core i7-975 (3.33@4.02 GHz, Bclk 175 MHz);
• motherboard: ASUS P6T7 WS SuperComputer (Intel X58);
• cooler: Noctua NH-D14;
• RAM: Kingston KHX2000C8D3T1K3/6GX (3×2 GB, DDR3-2000@1750, 8-8-8-24);
• video cards: ASUS ENGTX295/2DI/1792MD3/A and Inno3D GeForce GTX 295 Platinum Edition (GeForce GTX 295);
• hard disk: Samsung HD502HJ (500 GB, 7200 rpm, SATA-II).

Here testing was carried out in the Windows 7 x64 HP environment on an open bench. To create a load on the system, the OCCT 3.1.0 utility was used with a 30-minute power supply test using one card (the second was as an additional one), as well as while running the LinX 0.6.5 utility and the Tropics benchmark with activated anti-aliasing level 2x and anisotropic filtering 16x, while the video adapters worked in SLI mode. Another test was carried out with the launch of OCCT 3.1.0 in SLI mode at a resolution of 1366×720.

To measure the total power consumption of the system, the Seasonic Power Angel was used, which can also measure the power factor, voltage and frequency in the network, the consumed current and the amount of energy spent per unit of time. Net power consumption calculated based on 80 Plus certification – i.e. possible efficiency of the device. Errors in such calculations can be 5%. The voltages were checked with a UNI-T UT70D digital multimeter.

In addition, we decided to slightly expand testing by taking temperature readings inside the power supply, fan speed and noise level under a particular load.

The temperature was measured using the Scythe Kaze Master Pro panel, the sensors of which were located on the radiators inside the block and at a distance of 1 cm in front of the fan (#1) and behind the outer wall (#2).

For fan speed results, a UNI-T UT372 non-contact tachometer was used. The maximum speed was fixed for each of the power supply testing modes.

It should be borne in mind that such a technique at this stage is far from ideal and will be supplemented and changed as it is used.

Test results

The obtained data are entered in the table. In brackets for voltage are percent deviations from the norm, for power consumption – the approximate net load on the power supply.

Excellent stabilization, drawdown on the + 12V line is less than one percent, while overvoltage does not reach even two percent. In general, good performance for an affordable device on the CWT platform, especially since the block easily withstood a 15% overload.

conclusions

The first acquaintance with Deepcool power supplies left a positive impression on us. Model DQ750ST for its level is a well-made device that meets the energy efficiency requirements of 80 Plus Gold. In the range of standard loads, the unit emits a minimum of noise, which will allow you to assemble a very quiet and, given the excellent stability of the characteristics, a fairly powerful system from a pair of voracious video cards. And, it would seem, with a humane price tag, the DQ750ST could be an excellent choice for enthusiasts, but short cables and their minimum number can limit the scope of this block. It will fit perfectly into a system based on a MicroATX or Mini-ITX board with a small amount of drives, but for a standard ATX there may be nuances. Therefore, when choosing this model, you need to clearly understand whether the length of cables and connectors is enough to power internal devices, and only then become the happy owner of Deepcool DQ750ST.