Original Link: https://www.anandtech.com/show/11951/the-corsair-hx850-80plus-platinum-psu-review
The Corsair HX850 80Plus Platinum PSU Review
by E. Fylladitakis on October 24, 2017 8:00 AM ESTIn this review we are having a look at the latest revision of Corsair’s HX PSU series. The main improvements of the new series revision are an improved certification to Platinum, a fully modular design, and now an extended 10-year warranty. We are testing the HX850 model, suitable for 850W which can easily feed a powerful dual GPU gaming/workstation system.
Recent Power Supply Reviews
AnandTech tests a good number of power supplies each year, mostly in the popular power ranges (650-850W) with a few reviews now-and-again for small form factor parts or larger behemoths. Here are the power supplies we have reviewed in the last twelve to eighteen months.
- [link] The Corsair HX850 80Plus Platinum PSU Review (this review)
- [link] The Enermax Revolution SFX 650W PSU Review
- [link] The Seasonic PRIME Titanium PSU (650W, 750W, 850W) Review
- [link] The Riotoro Onyx Power Supply Review: 650W & 750W Tested
- [link] The BitFenix Whisper M 450W & 850W PSU Review
- [link] The Silverstone ST30SF & ST45SF SFX Power Supply Review
- [link] The Zalman ZM1200-EBT 1200W Power Supply Review
- [link] The SilverStone SX700-LPT SFX 700W PSU Review
The Corsair HX850: Introduction
Corsair released their first computer power supply units (PSUs) well over a decade ago. The first two units, the HX520W and the HX620W, first hit the store shelves back in 2006. The company has come a long way since then, as today they are one of the most reputable PSU manufacturers, marketing dozens of units through seven different product series. They also are one of the most influential companies, frequently introducing new platforms, upgrades, and innovative technologies.
Each of Corsair’s seven PSU series has been developed with a specific market group in mind. The company is constantly upgrading/adapting the products of each series with new revisions, but the specific market group for that series always remains unchanged. For example, their first series, the HX, was developed to target the demanding high-end market. The original HX520W and the HX620W are now but a distant memory, yet the HX series is still targeted towards demanding PC enthusiasts, consisting of eight high output (750-1200 Watt) units with very impressive specifications.
In this review we are having a look at the latest revision of the HX series, the HX850 (CP-9020138). This is the third revision of the 850-Watt HX unit, which was initially released with the first revision back in 2009. The most apparent upgrades of this latest revision are 80Plus Platinum efficiency levels and a fully modular design, plus an improved (10 year) manufacturer’s warranty.
Corsair HX850 (Rev 3) Power Specifications ( Rated @ 50 °C ) |
|||||
AC INPUT | 100 - 240 VAC, 50 - 60 Hz | ||||
RAIL | +3.3V | +5V | +12V | +5Vsb | -12V |
MAX OUTPUT | 25A | 25A | 70.8A | 3A | 0.8A |
150W | 850W | 15W | 9.6W | ||
TOTAL | 850W |
Internal Inspection
The 135 mm fan responsible for the cooling needs of the HX850 is the Corsair NR135P, a fan we frequently see in the company’s high-performance PSUs. Unfortunately, we cannot identify the OEM of the fan but we can tell that it is a quality model with a fluid dynamic bearing engine for longevity. It has a maximum speed of about 1500 RPM but, considering the unit’s output and efficiency, it is highly unlikely that it will be reaching this speed under normal operating conditions. The HX850 features full range fan control with a passive mode, meaning that the PSU’s thermal circuitry will not even start the fan unless airflow becomes necessary.
The OEM behind the latest version of the HX850 is Channel Well Technologies (CWT) design, a company that Corsair frequently trusts for their middle and high range products. They have been the OEM behind nearly all the HX series units to this date, with the exception of a few Seasonic designs many years ago. It is an upgrade of the version that the previous HX and RM units were using a few years back. This core design is currently being used for most HX and RM series PSUs, with small variations between the models.
The heatsinks of the HX850 are relatively small, even for an 80 Plus Platinum certified power supply. This is especially true for the secondary side of the PSU, where the heatsinks are small metallic braces with a volume of just a few cubic centimeters. A large portion of the heat dissipation on the secondary side is taking place underneath the PCB, towards the steel body of the unit. The APFC heatsink is thick but plain - essentially just a metallic slab with relatively little dissipation surface. Only the heatsink for the primary inversion circuit stands out, extending to form a small array of fins to increase its dissipation surface. Corsair is apparently placing a lot of faith in the efficiency of their latest design.
The filtering stage of the HX850 is typical for high output PSUs, with four Y capacitors, two X capacitors, and two filtering inductors. It has two conversion bridges with a small heatsink sandwiched in between them. The passive components of the APFC stage are two 400V / 470μF capacitors supplied by Nippon Chemi-Con and a very large filtering inductor that is partially wrapped into insulation material. The insulation material is probably not used mainly for protection but to prevent electromechanical vibrations that would result in noise (also known as “coil whine”). CWT extends this practice to nearly all the filtering inductors found inside their premium designs.
Two MOSFETs form an LLC resonant half-bridge inversion stage, whereas a horde of eight MOSFETs on the secondary side generates the 12V line of the unit. The 3.3V and 5V lines are derived via DC to DC conversion circuits found on the horizontal daughterboard at the edge of the PSU. All of the electrolytic capacitors are supplied by Nippon Chemi-Con, as are nearly all of the polymer capacitors as well. A couple of the polymer capacitors are supplied by Nichicon, ensuring that only capacitors from Japanese companies can be found in the HX850.
The Corsair HX850 80Plus Platinum PSU
External Appearance
The core aesthetic design of the Corsair HX850 is the same that the company has been using for years for their high-end units. It features a classy, understated design, with a satin black body and all-black cables. The chassis has chamfered edges and decorative stickers cover the largest portion of its sides. Further aesthetic improvements include embossed parallel ridges aligned with the fan’s finger guard wires and a small badge with the unit’s model at the rear side of the chassis. The chassis of the HX850 is 180 mm long, making it significantly longer than a standard ATX unit. This should not be a problem with any modern high-performance ATX case but caution is required with compact and atypical case designs.
Corsair moved the sticker with the unit’s specifications and certifications to the top of the chassis, allowing the user to hide it when the unit is installed with the cooling fan facing upwards. The side stickers are also installed in such a way so that the sticker facing the left panel of the case will always be upright. However, the sticker facing the right panel will always be upside down. Typical cases very rarely have a transparent right side panel but this could be a problem for custom designs. Still, a modder technically can remove and reinstall the side stickers without voiding the unit’s warranty, although keeping the sticker in pristine condition while removing it could prove to be a challenge.
The front of the chassis is littered with the connectors for the modular cables. Aside from the split 18+10 connectors for the 24-pin ATX cable, the rest of the connectors are essentially split into two groups: one group of five PCIe and CPU power connectors and one group of six SATA/Molex connectors. The PCIe and CPU cables share the same connectors on the side of the PSU. There is also a button that allows the user to switch from a single 12V rail mode to a multiple (seven) rail mode. When in multiple rail mode, the HX850 splits the 70.8A 12V output into seven virtual 40A lines, triggering an over-current protection shutdown if a single virtual line is overloaded. This mode provides additional safety and should be used by default, leaving the single rail mode only for competition overclockers or other special applications where a single device could momentarily require over 480 Watts and trigger a safety shutdown.
Packaging and Bundle
Corsair ships the HX850 in a large cardboard box with yellow/black artwork, which is becoming the company’s packaging insignia. The artwork is clean, with the front mainly focused on a picture of the unit itself and a lot of information printed on the sides and rear of the box. Inside the strong cardboard box, we found the unit well protected between thick foam paddings.
Strangely, the bundle of the HX850 is relatively frugal for a PSU of this class. Corsair supplies only the typical AC power cable, black 3M mounting screws, a very thorough multilingual manual, a case badge and a few short cable ties. There are no thumbscrews, cable straps, or other accessories.
The latest version of the HX850 is fully modular, allowing the user to remove even the 24-pin ATX cable. The SATA and Molex cables are flat, ribbon-like, but the larger PCIe and ATX/EPS power cables are normal round cables with black nylon sleeving. The cables are supplied inside a nylon storage pouch.
Corsair HX850 (CP-9020138) | ||
Connector type | Hardwired | Modular |
ATX 24 Pin | - | 1 |
EPS 4+4 Pin | - | 1 |
EPS 8 Pin | - | - |
PCI-E 6+2 Pin | - | 6 |
PCI-E 8 Pin | - | - |
SATA | - | 16 |
Molex | - | 6 |
Floppy | - | 1 |
Cold Test Results (Room Temperature)
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 new Corsair HX850 falls a little short regarding its 80Plus Platinum certification, failing to achieve >94% efficiency at 50% load with an input voltage of 230 VAC. This result however does not mean that the unit’s certifications are false, just that it received its efficiency rating with an input voltage of 110 VAC, under which the 80Plus directive is slightly more lenient. Also note that our ambient temperature is a little higher than the 25 °C recommended by the directive. Despite that, the HX850 has a very high average efficiency of 92.7% within its nominal load range (20% to 100% of the unit's capacity) and gave us fairly good efficiency readings under low loads.
The high efficiency of the Corsair HX850 allows the thermally controlled fan to stay inactive for a very large portion of the load range when the unit is operating in room temperature. Our test sample reached an output of nearly 400 Watts before the fan started to spin. The fan was relatively quiet thorough the entirety of our room temperature testing, reaching high noise figures only when very heavily loaded.
Output and Ripple Results
As it can be seen in the following tables, the electrical performance of the Corsair HX850 is outstanding even when subjected to high ambient temperatures. Our instruments recorded a maximum ripple of 28 mV on the 12V line under maximum load, an exceptional power quality figure for line outputting more than 63 amperes at the time.
Main Output | ||||||||
Load (Watts) | 171.81 W | 427.92 W | 637.89 W | 849.49 W | ||||
Load (Percent) | 20.21% | 50.34% | 75.05% | 99.94% | ||||
Amperes | Volts | Amperes | Volts | Amperes | Volts | Amperes | Volts | |
3.3 V | 2.23 | 3.34 | 5.57 | 3.33 | 8.36 | 3.31 | 11.14 | 3.3 |
5 V | 2.23 | 5.06 | 5.57 | 5.05 | 8.36 | 5.04 | 11.14 | 5.02 |
12 V | 12.62 | 12.13 | 31.56 | 12.08 | 47.34 | 12 | 63.12 | 11.99 |
The maximum ripple recorded on the 3.3V and 5V lines did not exceed 20 mV under normal load distribution and was only slightly higher with the HX850 heavily cross-loaded.
Line | Regulation (20% to 100% load) |
Voltage Ripple (mV) | |||||
20% Load | 50% Load | 75% Load | 100% Load | CL1 12V |
CL2 3.3V + 5V |
||
3.3V | 1% | 10 | 14 | 16 | 16 | 10 | 22 |
5V | 0.9% | 10 | 16 | 16 | 20 | 12 | 24 |
12V | 1.2% | 12 | 16 | 20 | 28 | 32 | 18 |
The voltage regulation is exceptional as well, with the 12V line staying within 1.2% across the nominal load range and the 3.3V/5V lines falling below 1%.
Hot Box Test Results
The impact that high ambient temperature has on the electrical performance of the Corsair HX850 is measurable but, considering the output of the unit and its thermal design, is relatively small.
The drop is almost linear across the entire load range, meaning that no components appear to be getting thermally overstressed at higher loads. The average nominal load (20-100%) efficiency dropped down to 91.2% during this test, but with an ambient temperature well above 45 °C.
Testing the Corsair HX850 inside our hotbox changes its thermal profile almost completely. The fan started almost right away this time and its speed was constantly increasing alongside with the load. From the relatively low internal temperature of the unit under these conditions, it appears that the cooling profile of the HX850 is aggressive, sacrificing comfort for safety. The unit will be intolerably loud when heavily loaded under such conditions but Corsair ensured that it will keep operating seamlessly and reliably, with its internal temperatures well within safety levels.
Conclusion
Corsair is aiming the entirety of the HX series, including the HX850 that we reviewed today, towards overclockers and advanced enthusiasts. These groups of users primarily value reliability and stability, but also need high overall performance, and are usually not dissuaded by a hefty price tag. The HX units are designed around that concept - the platform is primarily focused around the longevity of the PSU above everything else but without forgoing other performance aspects.
The overall electrical performance of the Corsair HX850 is exceptional. Even with the PSU heavily loaded under adverse operating conditions, the power quality readings that we took were excellent, with minimal voltage ripple appearing on all of the voltage lines and very strong regulation. Our readings were impressive but not unexpected of a high-quality modern PSU. The HX850 is not going to break any performance records here but pinnacle electrical performance is not the purpose of this series - Corsair has the AX series for that.
Our sample did not fully meet the 80Plus Platinum certification with an input voltage of 230V/50Hz, failing to surpass 94% efficiency at 50% load. As most companies do, Corsair is having their units tested and certified for an input voltage of 115V/60Hz and this specific unit has been officially tested and awarded an 80Plus Platinum certification, so there is nothing suspicious going on here. Apparently, the company’s engineers optimized the platform for an input voltage of 115V, as the lower requirements make it easier to achieve a better efficiency certification. Regardless of that, the conversion efficiency of the HX850 can definitely be characterized as excellent, with our sample sustaining an average efficiency of 92.7% across its nominal load range.
Although we feel that its heatsinks and overall thermal design could use an improvement, the high efficiency allows the Corsair HX850 to display very good thermal performance - perhaps even a little too good. The thermal control is very sensitive when the internal temperatures of the unit are high, pushing the 135 mm fan to its limit in order to keep the internal temperatures as low as possible. With the maximization of the unit’s reliability and stability being the primary design focus, that is not surprising, as even a few temperature degrees can mean years of difference on the lifetime of some electronic components, especially that of capacitors. The downside here is that the HX850 can become quite loud when forced to operate inside a very hot ambient environment.
At room temperature, the thermal behavior of the HX850 is entirely different, with the unit’s thermal control not even turning the fan on up until the load reaches almost half of the unit’s rated capacity.
The retail price of the Corsair HX850 currently is $160 (MSRP $200), which is a fair price for a high quality 80Plus Platinum certified unit that comes with a 10-year warranty. 80Plus Platinum units can nowadays found for less but most manufacturers have their leading designs priced around this price point and the HX850 is more than capable of giving the competition a run for their money.
The Corsair HX850 should be into the shortlist of anyone seeking a powerful, efficient, and very reliable PSU that will be the heart of their gaming/workstation system for many years.
Recent Power Supply Reviews
AnandTech tests a good number of power supplies each year, mostly in the popular power ranges (650-850W) with a few reviews now-and-again for small form factor parts or larger behemoths. Here are the power supplies we have reviewed in the last twelve to eighteen months.
- [link] The Corsair HX850 80Plus Platinum PSU Review (this review)
- [link] The Enermax Revolution SFX 650W PSU Review
- [link] The Seasonic PRIME Titanium PSU (650W, 750W, 850W) Review
- [link] The Riotoro Onyx Power Supply Review: 650W & 750W Tested
- [link] The BitFenix Whisper M 450W & 850W PSU Review
- [link] The Silverstone ST30SF & ST45SF SFX Power Supply Review
- [link] The Zalman ZM1200-EBT 1200W Power Supply Review
- [link] The SilverStone SX700-LPT SFX 700W PSU Review