The Corsair HX850 80Plus Platinum PSU Review
by E. Fylladitakis on October 24, 2017 8:00 AM ESTOutput 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.
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BurntMyBacon - Wednesday, October 25, 2017 - link
I should probably mention that there are a few different versions of prime supply differentiated by efficiency:Titanium:
https://www.hardocp.com/article/2016/07/21/seasoni...
Platinum:
https://www.hardocp.com/article/2017/06/13/seasoni...
Gold:
https://www.hardocp.com/article/2017/08/23/seasoni...
evilspoons - Tuesday, October 24, 2017 - link
As a Canadian who has to translate from USD to CAD all the time mentally, I'm always surprised when I find out you review your power supplies at 230V/50Hz (i.e. not in North America). I guess you get to do that bit of mental translation too.Good to know the Corsair supplies are still solid. I've had an HX750 since I bought my i7-2600k and it ran SLI 680s and an overclocked CPU since whenever that was. The 680s have since been replaced with a 1080 but if I ever need a PSU, shouldn't be too hard to choose...
Morawka - Tuesday, October 24, 2017 - link
It's funny how we've come full circle with power supplies. At first a Single 12V rail was desirable but nowadays, a Multiple rail system is preferred with the advent of virtual rails. I have a question. I have a RMI 1000x PSU from Corsair which also has Single and Multi-rail options. So is it generally preferred to keep it operating in multi-rail mode? Could a single 1080Ti or a 7900X CPU OC'd for example -- go over the 40A rating. (I think the RMi1000 has the same multi-rail setup as this one, albiet more rails.)TheWereCat - Tuesday, October 24, 2017 - link
1080ti can go easily to 40A when you unlock the power and voltage limit. Not by default as most if not all cards have power limit at around 355W.I flashed my FTW3 with XOC BIOS and I am easily hitting 400W (I am using the FTW3 air cooler) so I don't dare to push the card more even if I could but then the very high temps would lower my clocks significantly so it would be pointless.
DanNeely - Tuesday, October 24, 2017 - link
Yup. We started with multiple rails due to a max current safety requirement. Then PSU makers started ignoring that limit and making single giant rails. The standard was updated to allow this. (Were any compensatory safety requirements added?) The safety benefits from smaller overcurrent limits never went away though, so now we're seeing them added back to individual outputs.It'll be interesting to see if the PSUs that have an internal USB2 header cable and a control app let you customize the max for each output port separately instead of being a single all or nothing option.
Morawka - Tuesday, October 24, 2017 - link
I'll let you known if that's possible here in a couple of days as i'm building a 7900x with a RM1000i Power supply w/ Corsair Link. Being able to set the max amperage per 12v rail would be ideal for enthusiast.jonnyGURU - Monday, October 30, 2017 - link
To clarify.. we started with multiple +12V rails until PC Power & Cooling, at the time one of the largest PSU vendors, screwed up and didn't split rails up accordingly for their Turbo-Cool line. Instead of correcting the issue, they went rogue and said "screw this rail B.S.! Make everything single +12V rail!!!" Because their marketing was so strong, they brainwashed everyone into believing that the mistake wasn't on their end and so all the other vendors had to switch to single +12V rail as well to maintain their market share.FaaR - Wednesday, November 1, 2017 - link
I think you'd have to work hard to make a single GPU pull over 480W of power (;P), but if this worries you, just attach two power cables from different (virtual) rails for a total of 80 amps DC to your GPU.Of course, an 850W PSU isn't going to be able to supply that much juice just to your GPU, but you knew that already of course. :)
gammaray - Tuesday, October 24, 2017 - link
so if the HX serie is for "overclockers and advanced enthusiasts" what is the AX and RM series for?Morawka - Tuesday, October 24, 2017 - link
Corsair Link seems to be the separating feature. Well that and type 4 PSU cables that reduce voltage droop by implementing capacitors along each 12v wire. The RM series are mostly Gold certified whereas the AX series utilizes platinum efficiency with a Digital switching controller (also missing from the TX line)