Introduction

We would like to thank Corsair for supplying the review sample.

The HX series is the second top-of-the-line PSUs from Corsair that, previously, met only the 80 PLUS Silver certification. But the company made a massive upgrade to the four products comprising this series which have since earned 80 PLUS Gold certification. The OEM of the HX units remained the same, which is Channel Well Technology or CWT, a company which has a close working relationship with Corsair and has so far provided them with many excellent platforms.

In this review, we will evaluate the second stronger member of the HX series, the HX850, which, as its name implies, has a capacity of 850 W, so it will easily power a high-end system with up to three power hungry VGAs installed. The new HX850 PSU features a quiet operation at low loads/operating temperatures, since its thermally controlled fan only spins when it's needed. This is a technique that becomes more and more popular lately and significantly reduces noise output at low loads since the PSU goes fanless when the thermal load is low. Finally, the new HX850 sports a new and better look, thanks to the redesigned fan grill.

Specifications

With an efficiency of 80 PLUS Gold, the unit can deliver its max power continuously even at 50°C. The protections include all the usual ones except OTP (Over Temperature Protection), which, we believe, is crucial for a PSU. The cooling fan is equipped with double ball-bearings, so it will last pretty long and, finally, the PSU's length is much longer than the 160 mm usually seen.
The warranty period is very satisfactory at 7 years, while the price classifies the unit to the high-end category, where the competition is really tough. So the HX850 must perform very well in order to achieve a high price/performance ratio.

There is a single +12V rail that can deliver almost the unit's full power alone. This is very convenient for most users out there, since they won't have to bother about which cable/rail should be used for every component and, on top of that, modern systems are fed mostly by +12V. The minor rails are also pretty strong with 150 W max combined power, a power level that most likely won't be fully utilized by any contemporary system. Finally, the 5VSB can deliver up to 3 A, so it will easily cover most of the cases.

Cables & Connectors, Power Distribution

The PSU features numerous connectors including six PCIe and two EPS ones. However, at the same time, you can use either six PCIe and one EPS or five PCIe and two EPS connectors, something completely understandable if you take into account the unit's capacity.
The length of all cables is sufficient; however, the distance between the peripheral connectors is short, at only 100 mm. For SATA connectors, this may not be a significant problem, but for 4-pin Molex connectors it could cause trouble. Finally, the 24-pin ATX connectors use thicker 16AWG wires for lower voltage drops, while all other cables, except the FDD adapters, use the standard 18AWG gauges.

Since this PSU features a single +12V rail, we do not have anything to comment about its power distribution.

Packaging

The PSU comes in a large and long package. At the front, we find a close photo of the nice-looking fan grill and the curves on the casing that follow the lines of the fan grills. At the bottom right corner, there are several badges for the Gold efficiency certification, the 7-year warranty, and the ErP and C6 sleep state compatibility. Above the aforementioned badges, the model description is given.


At the bottom side, there is a list showing the PSU's dimensions along with the ATX and EPS compliances and the power input range. At the sides, only the model description is given along with a smaller image of the fan grill.


At the rear side of the box, one can see useful information about the characteristics and features of the unit. Besides the description of the available connectors and the power specifications table, there are also two graphs showing the fan's noise output and the efficiency curve at 115 V and 230 V.