Though ASUS as a company needs no introduction to regular AnandTech readers, even for us it's easy to overlook just how vast their range of product lines is these days. As the company has moved beyond PC motherboards and core components to kept diversifying over the years, they've established whole subsidiary brand names in the process, such as the “Republic of Gamers” or “ROG”. Nowadays, the ASUS logo can be found on almost every PC component and peripheral there is, from mouse pads to gaming laptops.

One of the many series of products ASUS is supplying under its brand name – and that, somehow, we've never reviewed up until now – is a rather extensive array of power supply units. The company splits its units into three main series, the ROG, the TUF Gaming, and the Prime, all of which are targeting higher segments of the market. In fact, ASUS is fairly rare in this respect; unlike most other manufacturers, ASUS largely stays out of the low-to-middle range of the market altogether, instead focusing on the more lucrative premium and gaming segments.

Today's review directs its focus towards ASUS's TUF Gaming series, which is – in our opinion – the most versatile series that the company currently markets. The TUF Gaming units are designed with long-term reliability and high performance in focus and are being marketed accordingly. The new 850W Gold variant of this series aligns with Intel's ATX 3.0 design guidelines, with the 80Plus Gold certification and 10-year manufacturer’s warranty as the major highlights, and retails for a reasonable price tag.

Packaging and Bundle

ASUS is known to be careful with their packaging and the box that the TUF Gaming 850W Gold is supplied in is no exception. The artwork on the box is detailed, with plenty of information to be found on the sides and rear of the box. The box is sturdy and the unit is well-protected inside to ensure safe shipping.

A fair bundle can be found inside the box of the TUF Gaming 850W Gold PSU. Aside from the typical AC power cable and the mounting screws, ASUS also supplies several cable ties, three quality cable straps, and a thick manual in 30 languages. There is also a “certificate of reliability” that indicates which tests the capacitors and chokes of the units had to pass for ASUS to use them. Most of them are done in accordance to the MIL-STD-202 and MIL-STD-810H standards, which gave ASUS the ground to boast about “military-grade reliability”. The tests are performed by iST, an independent laboratory based in Taiwan.

The TUF Gaming 850W Gold is a fully modular design, allowing for the removal of every DC power cable, including the 24-pin ATX connector. All of the cables are black, with black connectors and individually sleeved wires, including the ATX 24-pin and the new 12VHPWR cables. It is interesting to note that the total number of connectors is fairly low for a unit with that kind of capacity.

The ASUS TUF Gaming 850W Gold PSU

External Appearance

Externally, the TUF Gaming 850W Gold PSU is in direct contradiction to the “military” theme ASUS's marketing is heavily relying upon. The reason is that military designs are supposed to be entirely minimal and inconspicuous, while the designer of the TUF Gaming 850W Gold PSU practically left no part of the body untouched in an effort to create an aesthetically appealing product. Chamfered edges, embossed designs, graphic prints, debossed lettering – this unit has it all. The chassis is just 150 mm deep, which ensures compatibility with all but the smallest ATX-compliant cases.

Both sides of the chassis are heavily decorated but they are not identical. A cutout of the series logo can be seen on the left side, serving as a little cooling vent. There is no such cutout on the right side and the series logo is printed on the chassis instead. The entirety of the top side is covered by a sticker with the electrical specifications and certifications of the unit. The fan cutout at the bottom side of the TUF Gaming 850W Gold PSU is hexagonal instead of round.

Naturally, the front side of the PSU is home to the connectors for the modular cables. A basic legend is printed directly onto the body of the PSU in white paint. The series logo is subtly etched across the top part of the front side. The rear side is typical, with just the AC power receptacle and a basic on/off switch in sight.

Internal Design

The fan responsible for the cooling of the TUF Gaming 850W Gold PSU is a dual-ball bearing engine fan made by Champion, a Chinese manufacturer whose we very rarely encounter the products of inside PC components. The 135mm CF1325H12D has a maximum speed of 2100 RPM, which is very high for a fan of that size. ASUS markets the fan as an “axial-tech” technology fan, which basically is a plastic ring that connects the outer part of the fan’s blades, supposedly increasing the fan’s pressure.

The OEM behind the creation of the TUF Gaming 850W Gold PSU is Great Wall, a Chinese OEM that became known in the Western markets only a few years back when Corsair decided to use them for several of their mainstream products. The TUF Gaming 850W Gold is based on a platform that we have not encountered before and certainly is one of the latest Great Wall designs, developed to comply with the ATX 3.0 design guide requirements.

We can see that the main switch and AC plug receptacle are attached to a vertical PCB that also hosts a few of the filtering stage components, with the rest on the main PCB. The filtering stage is typical, totaling four Y capacitors, two X capacitors, and two filtering inductors. It leads to a dual input rectifying bridge configuration supplied by Leshan Radio Company (GBU15K), a Chinese company that we have never encountered before. The passive APFC components are two Rubycon 420V/390μF capacitors and a sizable filtering inductor.

All of the active components before the main transformer that need cooling are attached to a single long heatsink across the edge of the PCB. The primary side inversion circuit is a typical half-bridge LLC topology, with the two switchers also supplied by a company that we have never seen before (WAYON) and we could not find any datasheet for these particular chips (WMJ36N6N65SF2). Considering the PSU’s efficiency rating and half-bridge configuration, these definitely are very efficient low on-resistance MOSFETs but we have been unable to come by their exact specifications.

On the secondary side of the main transformer, six transistors from yet another manufacturer that we have never seen before (Jinlibo Electronics 4NA1R4C-A) form a conversion circuitry that generates the main 12V line. The secondary 3.3V and 5V lines are generated on the vertical daughterboard that is attached both to the main and the vertical PCB with the unit’s connectors. All of the electrolytic capacitors on the secondary side are supplied by Nippon Chemi-Con and Rubycon, while the solid-state capacitors are supplied by Nippon Chemi-Con and Nichicon.

Cold Test Results (~26°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. 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 overall efficiency of the ASUS TUF Gaming 850W Gold PSU is very good, with the unit easily meeting the 80Plus Gold requirements with an input voltage of 115V. Although the unit has its efficiency certification officially only with an input voltage of 115V, it would also pass the higher efficiency requirements and receive the 80Plus Gold certification with an input voltage of 230V if ASUS pursued it. The average nominal load range (20% to 100% of the unit's capacity) efficiency is 90.9% when powered from a 230 VAC source, which drops to 89.8% with an input voltage of 115 VAC. Generally speaking, the unit seems optimized for an input voltage of 230V, as there is a significant efficiency gap, especially at very high loads.

ASUS went with a semi-passive thermal design with an impressively lax cooling profile that has the unit operating fanless for more than half its entire load range. Once the fan starts, which would take a load of over 550 Watts at room temperature, it is barely audible. The fan speed quickly increases as the load reaches the maximum of the unit’s capacity but never becomes too loud. Conversely, the internal temperatures of the unit are allowed to climb significantly before the fan begins to spin, suggesting that ASUS’ engineers have a lot of faith in the resilience of this unit’s components.

Hot Test Results (~45°C Ambient)

The performance of the ASUS TUF Gaming 850W Gold PSU degrades measurably when the ambient temperature is high but not exceedingly so. Its average energy conversion efficiency across the nominal load range drops to 89.9% with an input voltage of 230 VAC and down to 88.8% with an input voltage of 115 VAC, translating to an average efficiency drop of 1% regardless of the input voltage. The drop is consistent across the entire load range, suggesting no significant thermal stressing exists on the unit’s major components.

Despite the very high ambient temperature, the ASUS TUF Gaming 850W Gold will still operate fanless when lightly loaded. As a result, the internal temperatures of the unit are high – significantly high for a PSU with that kind of output and efficiency. Component temperatures reach over 100 °C when the PSU is heavily loaded for prolonged periods under these conditions. There is a slightly higher efficiency degradation under maximum load than the rest of the operating range, suggesting marginal thermal stress on active components, but the effect is slight.

Even with an ambient temperature greater than 45°C, the fan does not start at all when the load is lower than roughly 220 Watts. Once it starts, it is relatively quiet at first but quickly speeds up to cope with the cooling requirements of the unit, becoming clearly audible at half load and reaching high noise figures at loads greater than 600 Watts. Regardless, it never reached its maximum speed, even when the unit was operating at maximum capacity.

Power Supply Quality

As part of our testing, we also check output parameters are within specifications, as well as voltage ripple and line noise.

Overall, the electrical performance of the ASUS TUF Gaming 850W Gold PSU is very good. It has strict voltage regulation on the major 12V line, fluctuating below 0.8% across the nominal load range. Regulation is not as tight on the 3.3V/5V lines, which are at 1.2/1.4% respectively, but these still are very good performance figures. The filtering on all voltage lines is very good, with optimal results at 50% load. The maximum ripple on all voltage rails occurred at maximum load, with a ripple of 16 mV / 16 mV / 30 mV on the 3.3V / 5V / 12V lines respectively.

As part of our standard testing, we test the primary protections of all PSUs we review (Over Current, Over Voltage, Over Power, and Short Circuit). All of the protections of the ASUS TUF Gaming 850W Gold are engaged normally. The over-current and over-power protection of the unit is markedly lax, allowing the draw of more than 140% of the unit's rated current and 125% of its rated capacity for seconds before shutting the unit down.

Conclusion

The ASUS TUF Gaming Gold power supply unit demonstrates a commendable level of build quality, underscored by the incorporation of high-quality Japanese electrolytic and solid-state capacitors. However, it is worth noting that a notable proportion of electrolytic capacitors and major active components stem from suppliers that may be unfamiliar to the seasoned observer.

Quality-wise, ASUS is placing a lot of resources on the marketing of some of their products as “military grade” equipment, which does raise the eyebrows of more experienced system builders and engineers. To begin with, military designs are minimalistic, often limited to baseline functionality, favoring low cost and resource readiness above everything else – and we can all agree that the design of the TUF Gaming 850W Gold PSU is anything but minimalistic.

What ASUS is doing is that they are having the inductors and capacitors certified by an independent lab to verify compliance with certain standards (in this case, a US Department of Defense standard) – an undeniably nice (and costly) procedure – but, truth is, the Nippon Chemi-Con and Nichicon capacitors found in this PSU are no different than any other of the same series. All equipment manufacturers typically certify their products according to a national or international standard because these are what those involved in the commercial market typically ask for. Some could very well have certifications proving compliance with the US DoD standards as they would need those to directly or indirectly supply certain organizations – we cannot know because manufacturers typically do not publish those test reports publicly. What is certain is that every quality equipment manufacturer certifies their products according to at least one official standard, because no sane equipment procurer would publish a tender or even request a quote for parts that do not come with at least one official certification attached. Finally, the US DoD electronics standards are not actually all that strict, and most of their test methods were issued somewhere between two and six decades ago, making it easy for modern materials and manufacturing procedures to outperform their requirements.

The OEM/ODM affiliation of the ASUS TUF Gaming Gold power supply unit is with Great Wall, a sizable Chinese manufacturer whose presence in mainstream and high-end PC power supply units has emerged only recently. The external design, while captivating, maintains a balance between aesthetics and functionality without veering into the realm of extravagance.

When evaluating power quality, the ASUS TUF Gaming Gold power supply unit offers commendable performance within its class. Its 12V line showcases precise voltage regulation, and the voltage filtering across all voltage rails is notably effective. The energy conversion efficiency surpasses the requirements stipulated by the 80Plus Gold certification, regardless of input voltage conditions.

In terms of thermal performance, the ASUS TUF Gaming Gold exhibits a noteworthy level of resistance to thermal stress. However, in demanding scenarios with extreme loads and elevated ambient temperatures, the cooling profile's relatively lax nature leads to elevated operating temperatures. In terms of acoustics, the ASUS TUF Gaming Gold power supply unit is virtually noiseless during typical operating conditions, even when subjected to substantial loads. The integrated fan remains dormant until the unit's load surpasses fifty percent of its total capacity, contributing to a serene computing environment.

In light of its features, performance, and affordability, the ASUS TUF Gaming Gold offers excellent value at its current price point of $111 in the US. This competitive pricing, combined with its compliance with the ATX 3.0 standard, positions the unit as an attractive choice for those seeking a high-performance power supply solution. Despite minor caveats, the ASUS TUF Gaming Gold stands as a compelling option, addressing the needs of PC enthusiasts and professionals alike, making it a worthy addition to the ASUS TUF Gaming lineup.