The DeepCool PX850G 850W PSU Review: Less Than Quiet, More Than Capable

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Written By Pinang Driod

DeepCool is one of the few veterans in the PC power & cooling components field still active today. The Chinese company was first founded in 1996 and initially produced only coolers and cooling accessories, but quickly diversified into the PC Case and power supply unit (PSU) markets. To this day, DeepCool stays almost entirely focused on PC power & cooling products, with input devices and mousepads being their latest diversification attempt.

Today’s review turns the spotlight toward DeepCool’s PSUs and, more specifically, the PX850G 850W ATX 3.0 PSU, which currently is their most popular power supply. The PX850G is engineered to balance all-around performance with reliability and cost, all while providing ATX 3.0 compliance. It is based on a highly popular high-output platform but, strangely, DeepCool rated the PX850G for operation up to 40°C.

DeepCool PX850G
Power specifications ( Rated @ 40 °C )
RAIL +3.3V +5V +12V +5Vsb -12V
MAX OUTPUT 22A 22A 70.8A 3A 0.3A
120W 849.6W 15W 3.6W
AC INPUT 100 – 240 VAC, 50 – 60 Hz
MSRP $113

The DeepCool PX850G 850W PSU comes in straightforward packaging, with a minimalist cardboard box accented by a decorative ribbon for a bit of flair. The unit is well-protected during shipping, enclosed in a nylon bag and surrounded by foam inserts. Key specifications and an overview of the PSU’s performance are clearly printed on the rear side, giving browsing buyers a quick glance at what to expect from the product.

DeepCool supplies the typical necessary mounting screws and AC power cable, but also a jump-start adapter and four reusable cable straps for a little additional value. There is also a small envelope with documentation inside.

This power supply unit is distinguished by its fully modular design, allowing for the detachment of all DC power cables, including the 24-pin ATX connector. The cables are black, from their connectors to the wires. All are without sleeving, creating a uniform visual design.

DeepCool PX850G
Connector type Hardwired Modular
ATX 24 Pin 1
EPS 4+4 Pin 2
EPS 8 Pin
PCI-E 5.0 1
PCI-E 8 Pin 3
Molex 4

External Appearance

The DeepCool PX850G 850W PSU is housed in a chassis that measures 86 mm × 150 mm × 160 mm (H × W × D), making it just a bit longer than the typical ATX standard dimensions. This size allows the power supply unit to integrate smoothly into most tower PC cases, with the sole exception being compact and some HTPC/Cubic PC case designs. Despite its size, the length is a necessary sacrifice for the unit to accommodate its 135 mm cooling fan.

DeepCool has focused on the external design of the PX850G 850W PSU, reflecting a balance between aesthetics and functionality. The power supply unit sports a satin black finish, with the company’s logo discreetly punched on both sides of the chassis. The integrated fan finger guard showcases a distinctive square design, differentiating it from typical round guards. An information sticker, detailing the PSU’s specifications and certifications, is located on the top of the unit.

Typically, the power switch and AC input receptacle can be found on the rear side, with a push button that can be used to turn the hybrid fan mode off and force the unit’s fan to stay on at all times. The front side is dedicated to the modular connectors, each with a simplistic white label for quick identification. A standout feature is the inclusion of a turquoise 12VHPWR connector, underscoring the unit’s compliance with the latest ATX 3.0 standards with a little bit of visual flair.

Internal Design

The DeepCool PX850G 850W PSU comes with a Hong Hua HA13525H12SF-Z 135 mm fan, featuring an FDB engine. These fans are popular and known for their high quality. This particular fan operates at a very high maximum speed of 2300 RPM, an impressive figure for a 135 mm fan tasked with cooling an 850W unit.

The DeepCool PX850G 850W PSU is crafted by Channel-Well Technologies (CWT), a distinguished OEM renowned for its expertise in developing mid to high power output PC power supplies. CWT’s legacy as a venerable OEM is well-established, with their platforms found in some of the most popular products of all time.

The DeepCool PX850G 850W PSU architecture is based on tried and true topologies, with no surprises to be seen. At the power supply’s input, the filtering stage is slightly enhanced over the minimum baseline suggested by the ATX design guide, featuring four Y capacitors, two X capacitors, and two filtering inductors. This is followed by two rectifying bridges, both attached to their dedicated heatsink. The Active Power Factor Correction (APFC) circuitry takes a significant amount of space, with the main heatsink holding the active components along the PCB’s perimeter. The APFC transistors are two Infineon 6R125P6 MOSFETs and a diode. The APFC also includes an encased filtering inductor and two large capacitors (a Nippon Chemi-Con 330 μF and a Rubycon 470 μF).

In the primary inversion stage of the DeepCool PX850G 850W PSU, a half-bridge LLC topology is implemented, with the two power transistors mounted on a substantial dedicated heatsink—a configuration prevalent in modern power supplies for its low cost and dependability. The secondary conversion stage consists of six Onsemi 5C430N transistors on a vertical daughterboard, generating a single 12V output. The 3.3V and 5V outputs are managed by DC-to-DC conversion circuits on another daughterboard.

On the secondary side, the DeepCool PX850G 850W PSU features capacitors from Rubycon and Nippon Chemi-Con, alongside several Nichicon polymer capacitors. This mix of highly reputable Japanese manufacturers makes the PX850G an all-Japanese affair which assists both the company’s marketing efforts and the consumer’s peace of mind.

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs – 2014 Pipeline post.

The DeepCool PX850G 850W PSU meets the standards set by the 80Plus Gold certification, even if only barely. When operating with a 115 VAC input, the PSU displays an average nominal load efficiency of 89% across a range from 20% to 100% of its capacity, which increases to 90.5% with a 230 VAC input. The efficiency peaks at a load slightly less than half its maximum capacity. Low load efficiency is excellent, substantially better than that of most units with a similar power output.

The DeepCool PX850G 850W PSU features a “hybrid” fan mode, allowing the fan to remain inactive until required, which contributes to its quiet operation under low to medium loads. In ambient room temperature, the fan starts when the load surpasses 400 Watts. Once on, the fan accelerates aggressively as the load increases. Due to the aggressive fan profile at higher loads, the internal temperatures of the unit are maintained at relatively low levels, indicating that the design prioritizes reliability over acoustics.

During its hot testing phase, the DeepCool PX850G 850W PSU exhibits a significant decrease in efficiency, with figures dropping to 87.9% under a 115 VAC input and 89.5% with a 230 VAC source, compared to 89% and 90.5%, respectively, during cold testing. The drop is substantial but almost equally distributed across the load range, which bodes well for the quality and longevity of the unit. Despite the efficiency reduction in higher ambient conditions, there is no sign of thermal stress at peak loads, even though this unit is rated for operation at an ambient temperature of up to 40 °C.

In hot testing conditions, the fan of the DeepCool PX850G 850W PSU activates at approximately 250 Watts, quickly ramping up to maximum speed as the load approaches 85% capacity. This behavior ensures the PSU remains relatively quiet up to half load but, beyond that point, the noise level significantly increases and makes the unit quite loud. This aggressive fan profile effectively manages heat but results in poor acoustics performance during heavy use.

Obviously due to the overzealous 135 mm fan, the DeepCool PX850G 850W PSU adeptly handles its thermal output, keeping internal temperatures commendably low for its category. During operation with loads exceeding 80% – a range at which the fan runs at its peak speed – the PSU effectively prevents temperatures from even nearing unsafe thresholds, ensuring it remains safely below the limits that would activate the over-temperature protection (OTP) feature or instantly damage any of its components.

The electrical performance of the DeepCool PX850G 850W PSU stands out in its class, showcasing exemplary voltage regulation and ripple suppression. The 12V rail maintains a tight 1.2% variance, with even more precise performance on the 3.3V and 5V rails. Ripple suppression is where this unit shines brightly, with maximum values recorded at 20 mV for the 12V line, 18 mV for the 5V line, and 16 mV for the 3.3V line, ensuring that the PSU provides consistently clean power across diverse load conditions. These figures outclass many top-tier products that cost multiple times as much as the PX850G does.

Main Output
Load (Watts) 172.62 W 429.86 W 641.65 W 853.57 W
Load (Percent) 20.31% 50.57% 75.49% 100.42%
  Amperes Volts Amperes Volts Amperes Volts Amperes Volts
3.3 V 1.99 3.36 4.97 3.35 7.45 3.35 9.94 3.34
5 V 1.99 5.1 4.97 5.09 7.45 5.06 9.94 5.06
12 V 12.79 12.18 31.98 12.13 47.97 12.07 63.96 12.04
Line Regulation
(20% to 100% load)
Voltage Ripple (mV)
20% Load 50% Load 75% Load 100% Load CL1
3.3V + 5V
3.3V 0.7% 12 10 16 16 10 14
5V 0.7% 8 12 12 18 12 12
12V 1.2% 18 14 16 20 18 16

During our routine evaluation, we examine the fundamental protection features of all power supply units we review, including Over Current Protection (OCP), Over Voltage Protection (OVP), Over Power Protection (OPP), and Short Circuit Protection (SCP). The DeepCool PX850G 850W PSU passed all key protection tests, demonstrating its effectiveness in safeguarding against scenarios that might endanger the PSU or attached components. It exhibited slightly loosely calibrated Over Current Protection (OCP) for the 3.3V and 5V rails, activating at 130% for both, which is high but not to the point we would consider it to be a major concern. The 12V rail’s OCP activation at 126% aligns well with expectations for an ATX 3.0 compliant PSU, ensuring robust protection while not being oversensitive to power excursions.

In the competitive landscape of power supply units, the DeepCool PX850G 850W PSU distinguishes itself as an appealing choice for users aiming for a fusion of performance, quality, and reasonable cost. DeepCool’s approach with the PX850G centers on leveraging high-quality components and reliable designs, intending on balancing every performance aspect with a touch of unique aesthetics. Although the design notion was sound, the PX850G could be much more balanced in most ways.

Electrical performance is where the PX850G undoubtedly excels. In particular, the power quality of the PSU is splendid, outclassing many top-tier products that come with much heftier price tags. On the other hand, the energy conversion efficiency of the PX850G could be a little better, as the unit barely met the 80Plus Gold compliance requirements. It does have exceptional low load efficiency but its average nominal load efficiency is a tad lower than that of most comparable products.

Constructed by Channel-Well Technologies (CWT), a venerable OEM recognized for their excellence in the mid to high-range PSU sector, the PX850G boasts exceptional build quality. This confidence is likely behind the offering of a solid 10-year warranty. Opting for a 135 mm fan and significant heatsink dimensions, the design meticulously addresses cooling and thermal efficiency. The PSU’s thermal management adeptly keeps temperatures in check, with the very low internal temperature readings substantiating the longevity and reliability of the PX850G. However, the noise levels under heavy loads also mark the PX850G’s most significant drawback. While the unit performs quietly under lower demands, the sound becomes much more pronounced as the load intensifies, which may not align with all users’ preferences for a quiet operation.

The $113 retail price of the PX850G strikes a middle ground, presenting a fair proposition when considering its ATX 3.0 compliance, superior build quality, good overall performance, and the assurance of a decade-long warranty. Despite the potential concern over noise at high loads that can drive a portion of potential buyers away, the DeepCool PX850G 850W PSU represents a reasonable choice for enthusiasts who do not overly stress their hardware and want a product blending great electrical performance, quality, and a sensible price with the assurance of compatibility with forthcoming hardware.



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