Cooler Master V 850 SFX Gold ATX 3.0 power supply review

In response to the increasing popularity of compact and portable gaming PCs over the past couple of years, we have seen several PC peripheral manufacturers release larger collections of SFX form factor cases and power supplies. Chief among these has been Cooler Master, where the prolific PC part vendor recently expanded their SFX series to include ATX 3.0-compliant PSUs. This has finally given the company a modern, miniature platform that can drive the latest Nvidia video cards.

We take a closer look at Cooler Master's V850 SFX Gold, a more budget-friendly option in the SFX power supply market compared to their previously reviewed V1100 SFX Platinum, to see if it belongs on our list of best power supplies. The SFX Gold series comprises four models, ranging from 550W to 850W, with the 850W unit we are reviewing today being the most powerful. This 850-Watt power supply is certified 80 Plus Gold and designed for high-performance gaming and workstation builds. As the top-tier model in the SFX Gold series, it offers substantial power output for an SFX unit while maintaining ATX 3.0 compliance, featuring a 12+4 pin connector in a compact SFX format.

Specifications and Design

In the Box

Cooler Master packages the V850 SFX Gold in a robust and attractively designed cardboard box. The box's striking color scheme ensures it catches the eye on store shelves, while comprehensive details about the PSU and its features are provided on the sides and back of the box. Inside, the power supply is securely packaged with substantial foam, which is tailored to safeguard the unit during shipping.

Unlike what was the case with the Platinum series models, the bundle of the V850 SFX Gold is extremely frugal and limited to the necessary AC power cable and a basic leaflet. Strangely, the company advertises that the unit comes with an SFX-to-ATX adapter, but we found no such adapter included with the sample we received.

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The Cooler Master V850 SFX Gold is a fully modular PSU, allowing for the detachment of every cable, including the 24-pin ATX cable. The connectors and wires are uniformly black, featuring ribbon-like "flat" wires, except for the 12VHPWR cable, which is sleeved. The cables are shorter than those typically found in ATX PSUs, which is advantageous for smaller cases and compact system builds where space is at a premium. The total number of connectors is somewhat limited, given the power output of this model. However, a closer look at the 12VHPWR connector reveals that this cable limits the maximum power draw to 450 Watts. This would be perfectly acceptable for the less powerful units of the series, but not ideal on a product capable of outputting at least 850 Watts – unless it could not handle the power excursion requirements. Nonetheless, this connector can limit compatibility and overclocking with powerful graphics cards.

External Appearance

A quick look at the Cooler Master V850 SFX Gold highlights its most basic achievement, with the company’s engineers having successfully created a platform capable of delivering 850 Watts of continuous power within the compact dimensions of a standard SFX form factor chassis, measuring 125 × 63.5 × 100 mm / 4.92 × 2.5 × 3.94 in (W×H×D). While the power-to-mass ratio of the V850 is commendable, it does not surpass the highest ratios we have observed in previous reviews. It would be very difficult to increase power density further without substantially increasing efficiency. Otherwise, thermal performance would become a major concern.

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The chassis of the V850 SFX Gold adheres to the standard SFX size and is finished in a matte black paint. The left side of the unit features a distinctive geometric, C-like design, with the company and series logos prominently displayed in the center. A large sticker on the top side of the chassis provides the unit's certifications and specifications.

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The rear side of the Cooler Master V850 SFX Gold is relatively straightforward, featuring the necessary AC cable receptacle and a small on/off switch, which is a practical addition given the unit's compact size. The front side of the unit is densely arranged with connectors for the modular cables. Although these connectors are not color-coded, a basic legend is printed directly on the chassis to help identify each connector's function. All connectors are keyed to ensure correct and secure connections.

Internal Design

The 92 mm fan cooling the Cooler Master V850 SFX Gold is produced by Hong Hua (HA9215VH12FD-F00), a well-known manufacturer of high-quality fans. This low-profile fan, measuring only 15 mm in thickness, reaches a maximum speed of 3000 RPM, which is very high, reflecting the need to efficiently manage heat in such a power-dense unit. It utilizes a fluid-dynamic bearing that offers extended durability and operates slightly more quietly compared to standard ball-bearing fans.

The OEM behind the creation of the Cooler Master V850 SFX Gold is a company called Gospower, and this is the first time that we've encountered one of their platforms. Founded in 2006 in China, they are a relatively new OEM of power electronic products, with the company focusing primarily on solar power products.

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The interior of the Cooler Master V850 SFX Gold is remarkably dense, illustrating a masterful design approach to component arrangement. The filtering stage begins immediately behind the AC receptacle and includes an impressive array of components, given the limited space: four Y capacitors, two X capacitors, and two filtering inductors — a comprehensive setup for a compact design. The unit features a single bridge rectifier, mounted on its own heatsink. There is a single bridge rectifier mounted on its own heatsink, which, though simple, provides adequate surface area and openings to facilitate airflow.

The APFC circuit is textbook, but the active components share the same heatsink as the primary side inversion circuitry. The passive components are a massive 420V/730μF from Nippon Chemi-Con and a coil that takes about 15% of the unit’s space all by themselves. On the primary side of the transformer, we find two 65T130F inversion MOSFETs that form a typical half-bridge LLC converter topology.

Cold Test Results

Cold Test Results (25°C Ambient)

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.

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The efficiency of the Cooler Master V850 SFX Gold is commendable, consistently meeting the 80Plus Gold certification standards across different voltage inputs. It achieves higher efficiency when powered via a 230V AC source, with an average efficiency of 91.6% across the nominal load range. When powered from a 115V AC source, the efficiency decreases significantly, to 89.2%, but it still remains well above the threshold required for the 80Plus Gold certification.

Despite its high efficiency, the Cooler Master V850 SFX Gold exhibits higher internal temperatures than might be expected. This is primarily due to the unit's compact and dense design, which limits its cooling capacity compared to larger ATX units. Consequently, the internal temperatures are higher than typical for power supplies with similar efficiency levels. However, these temperature levels remain within safe operational limits for the unit.

Cooler Master initially advertised this unit as having a zero-RPM fan mode, but corrected that claim a few weeks after the unit was released. The 92 mm fan begins operating as soon as the PSU is powered up, even with no load at all, although it remains relatively quiet under low load conditions. As the load increases, the fan's speed gradually escalates, becoming far louder when the load exceeds 600 Watts. Due to its very compact size and small fan, the PSU can become very loud under very high load conditions, which is expected given the challenging cooling demands of such a design.

Hot Test Results

Hot Test Results (~45°C Ambient)

Despite experiencing very high internal temperatures, the Cooler Master V850 SFX Gold displays only subtle signs of thermal stress. Even under conditions of elevated ambient temperatures, the impact on performance is measurable but small. The efficiency reduction is modest, with only slight decreases observed across the nominal load range, and the losses remain relatively low even when operating at or near maximum capacity. This indicates that the unit's components are handling the very high temperatures without issue.

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Despite the small fan's best efforts, the internal temperatures of the Cooler Master V850 SFX Gold can exceed 130°C when the unit is heavily loaded within a high-temperature testing environment. These temperatures are very near the PSU's thermal shutdown threshold, indicating that reaching this limit could be imminent under such conditions. In any case, operating this unit at such high temperatures for prolonged periods of time will severely reduce its lifespan.

The 92 mm cooling fan of the Cooler Master V850 SFX Gold starts at a high speed and is immediately audible. The fan rapidly accelerates and reaches its maximum speed when the load is only at 50% capacity. Beyond this point, the fan can do no more to mitigate heat, which explains why the internal temperatures of the unit can reach such elevated levels. This design suggests that the V850 SFX Gold is not intended for use in extremely hot environments or under consistently heavy loads.

PSU Quality and Bottom Line

Power Supply Quality

The electrical performance of the Cooler Master V850 SFX Gold is impressive, showcasing outstanding voltage regulation across all rails and excellent line filtering on all voltage lines. The unit maintains strict voltage regulation of roughly 1% on all voltage lines. Filtering is exceptional, with very low maximum ripple values of 24 mV on the 12V rail, 22 mV on the 5V rail, and 20 mV on the 3.3V rail, that ensure clean and stable power delivery.

The unit also performs well in tests of its primary protections, including Over Current, Over Voltage, Over Power, and Short Circuit, indicating robust safety mechanisms. However, the Over Current Protection (OCP) settings are a bit lax on the 12V rail, at 130%. The Over Power Protection (OPP), measured under hot conditions, shows a setting of 124%. These figures may actually seem low for an ATX 3.0-compliant unit, but technically are high considering the thermal stress this unit receives.

Bottom Line

In the realm of compact power supplies, the V850 SFX Gold is a workable contender. Its 850-Watt output and 80 Plus Gold efficiency certification are commendable, providing ample power with reasonable efficiency and a viable price tag. Despite some limitations, particularly the maximum 450-Watt power draw limit for the 12VHPWR connector, the V850 offers substantial functionality within its compact SFX format. This design choice, while somewhat restrictive for high-end gaming setups requiring more power for sustained peak performance, still accommodates a broad range of mainstream graphics cards and computing tasks.

Moving on, the Cooler Master V850 SFX Gold showcases a sleek and understated aesthetic that complements any high-end PC build. The chassis, finished in a uniform matte black, features a distinctive geometric, C-like design on the left side, accentuated with the Cooler Master and series logos prominently displayed. This minimalist yet elegant design ensures that the unit not only performs well but also looks good in any small form factor or open-case setup. In terms of electrical performance, the V850 SFX Gold impresses with excellent voltage regulation and line filtering. The ripple suppression is particularly noteworthy, maintaining low maximum values across all rails, which ensures stable power delivery to sensitive components. The primary protections, including Over Current, Over Voltage, and Over Power, function adequately, though the settings are slightly conservative compared to other ATX 3.0 compliant units.

The overall performance of the V850 SFX Gold is not without limitations, particularly when it comes to thermal performance and noise. The unit operates with a 92 mm fan that starts at a noticeable speed and rapidly accelerates under load, quickly reaching very high speeds, especially in very hot operating environments. This aggressive fan curve is necessary due to the high internal temperatures, which can surpass 130°C under extreme conditions. Under testing conditions, the unit exhibited higher internal temperatures than typical for power supplies of similar capacity and efficiency. This could be attributed to its dense internal layout and compact size, which, while impressive in terms of space efficiency, impose significant thermal challenges. Despite these temperatures, the unit performs within safe operational limits, although the proximity to thermal shutdown thresholds suggests that Cooler Master has pushed the limits of what's possible in such a compact form factor - with that platform and level of complexity, at least.

With that said, the retail success of this power supply will, in some respects, be in spite of Cooler Master rather than because of them. The launch of this PSU came with a series of unusual and unforced marketing stumbles on Cooler Master's part.

Initially, the PSU specs and marketing materials inaccurately claimed that the PSU features a zero-RPM fan mode – a desirable feature for reducing noise that is not actually available in the product. This claim has since been removed from the website and marketing materials. Other, more minor snafus still remain. Cooler Master advertised the inclusion of an SFX-to-ATX adapter, for example, but it's not actually in the product box. Finally, claims that the PSU's capacitors are Japanese-made are technically correct but misleading, as only the primary side capacitors meet this standard.

None of these are fatal for hardware that is, at its core, a solid design. But these kinds of silly specification discrepancies can unnecessarily undermine confidence in the brand's reliability and transparency.

Conclusively, the Cooler Master V850 SFX Gold represents a fair option for users who need a compact, efficient, and reasonably powerful PSU, backed by a 10-year manufacturer's warranty. Its price point of $120 is fair, considering the performance and the compliance with ATX 3.0 standards. However, potential buyers should weigh its thermal and acoustic characteristics and the limitations posed by the power draw of the 12VHPWR connector. For those building compact systems without extreme power requirements, the V850 SFX Gold offers great electrical performance, ensuring stability and reliability where it counts.

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