Corsair HX850 V2 Power Supply Review Page: 1

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Introduction

We first reviewed a HX series back in November 2006, oh how time has flown by. Back then they ever had a red sticker design, who can remember these? All that time ago a 620W PSU cost £96 and only just scraped by with 83% efficiency! In June 2009 we reviewed the original HX850 and it was so good it won our "Best in Class" for 850W to 1000W units. Corsair have just released a revamped V2 version of the HX850 with a new efficiency rating and some interesting new features. Its time to break out the Sun Moon tester and hot box to see how the new one stacks up against the competition on the market today. Lets just hope I don't wake the kids up.....!


Specifications

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Packaging

You would be mistaken for thinking this was the the HX850 V1 box, but then that's because Corsair has been using the same design template for some time now. The only real difference from here is the different fan grill and the inclusion of a Gold efficiency and a 7 year warranty badge.

Corsair PSU new    Corsair PSU new  

Corsair PSU new    Corsair PSU new  

Inside the box it is also very standard Corsair, we still have not found a use for the velvet bag once you have actually fitted your PSU.... post your ideas in the forum thread!  



Corsair HX850 V2 Power Supply Review Page: 2

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Up Close & Cables

Other than the fan grill there really isnt much to tell the V1 and the V2 apart other than some subtle sticker design differences.

Corsair PSU new  Corsair PSU new

  
The braiding on the fixed cables isnt that bad but it's also not that great either, it feels like a standard braid though and we have seem much worse on power supplies even recently. The coloured wires beneath is what makes things look rather dated.

Corsair PSU new  Corsair PSU new

  
The modular cables come in the standard Corsair cable bag, if you have never owned a PSU that comes with one of these they really are handy for keeping all your cables together for that moment when you want to add something to your rig they are all in once place safe and it makes them much easier to find should under your bed look like the inside of a bin bag!


Corsair PSU new  Corsair PSU new

When we actually get a good up close look at the modular cables they look much cleaner than the fixed cables. The main reason is the wires used are actually black, even thought the braid is the same you can easily see how much cleaner and modern these look. The trouble is when in assembling the units in the factory its much easier to solder cables to the right place when they are colour coded, making them all black makes things much harder. There are many ways around this but would add assembly time and there for most cost.

Corsair PSU new  Corsair PSU new  

Corsair PSU new  Corsair PSU new  



Corsair HX850 V2 Power Supply Review Page: 3

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Simulated Load Results (Graphs)

Because I understand that not everyone enjoys getting a headache from trying to read the tabulated results over on page 4, this page is dedicated to some pretty looking graphs that sum up the majority of the results in an easily digestible format. 

When viewing the graphs you need to bear in mind that the highest and lowest values on the Y-axis (voltage) represent the maximum and minimum voltages allowed by ATX specifications. If the results should fall outside the graph at any time, then that's an instant FAIL. However, merely staying inside these boundaries does not necessarily indicate a good PSU. In order to display truly great voltage regulation, a PSU must stick as closely as possible to the thick white horizontal line (ideal voltage) as possible.

You will also notice that the graph is split into three sections as depicted by the Green, Amber and Red backgrounds. These indicate normal usage (green), heavily uneven load distribution (amber) and overloading of the PSU (red). For the most part all we need to worry about is how it performs in the green section, but good performance in the other sections will undoubtedly earn the PSU extra brownie points.


Starting with the +3.3v rail, the HX850 offers a very gentle downward gradient across the normal load results (T1-T4) indicating excellent stability. Furthermore, the near-Idle results in T1 come out at 3.34v showing that Corsair have not attempted the age-old trick of over-volting the output at idle to make the full load results seem more favorable. Both of the cross-load voltages are pretty much perfect as well - the first time I've ever seen such a result in any PSU tested on OC3D.


The +5.5v rail tells a similar story with not much of a dip in voltage from idle to full load under the normal tests. The only real difference is that the idle voltage starts a little higher at 5.05v, bringing the rest of the results up a tad and placing the voltage output during test 3 at exactly 5.00v. Once again, the cross-load results are easily the best I've ever seen with almost perfect voltage outputs.


As I've come to expect form Corsair PSU's, the +12v rail results during normal load tests are so flat that I could park my car on them with the hand-brake off. Manufacturing a PSU that drops only 0.16v from idle up to 852w is no mean feat, and it's good to see that Corsair haven't let their standards slip over the years with the release of their new line-up. Best of all though is the TMax result that drops to only 11.80v when running at a whopping 1081w - 231w over spec.

 

Finally we come to the tree hugging and money saving bit. Corsair have had the HX850 certified as an 80Plus Gold unit, which essentially means it must be 87% efficient at 149.6w / 850w loads, and 90% efficient at 425w. As we can see, that is absolutely no problem for the HX with just over 91% efficiency or greater in all of the standard tests. Only when we apply the extreme cross loads does the % levels drop but this is not part of the ATX specifications. Its worth noting by our tests this would pass the levels needed for a platinum rated efficiency! 

If you're interested in how the HX performed under the oscilloscope. Read on....



Corsair HX850 V2 Power Supply Review Page: 4

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Simulated Load Results (Tables)

If you've seen the simplified graphs over on the previous page you will undoubtedly already have a good idea of how the HX850 performs. However, certain results from the test can be too difficult to incorporate into the existing graphs, and for this reason all of the result data is also provided in the table format below. 

All testing is conducting using OC3D's trusty SunMoon SM-268+ DC load tester. This equipment is capable of placing a user specified load on all of the PSU's rails (+3.3v, +5v, +12v, -12v, +5vSB) up to a maximum load of 1680w.  As the maximum load for this device on the +12v rail is restricted to 75A we can also call on additional help from our Analogic Series 2000 DC load tester, so that anything up to an additional 166A can be added if necessary.

As usual, all testing is conducted at 50°C (±5%) with the results being recorded using a Fluke Multimeter and Thermostat.

Corsair HX850 @ 50c
  +3.3v +5.0v +12v +5vSB -12v AC Watts /
 DC Watts
 Efficiency Intake /
 Exhaust
Δ Temp
Test1
(25%)
4.50A4.50A14.25A0.75A 0.20A236w /
216w
91.52%49.6°C /
49.7°C
0.1°C
3.34v5.05v12.08v5.05v -11.56v
Test2
(50%)
9.00A9.00A28.50A1.50A 0.40A

461w /
430w

93.27% 50.2°C /
50.2°C
0.0°C
3.32v5.02v12.04v5.02v -11.54v
Test3
(75%)
13.50A13.50A42.75A2.25A 0.60A688w /
642w
 93.31%50.5C /
50.5°C
0.0°C
3.30v5.00v11.98v4.99v-11.53v
Test4
(100%)
18.00A18.00A57.00A3.00A0.80A930w /
852w
91.61% 51.2°C /
52.6°C
2.4°C
3.27v4.97v11.92v4.95v-11.54v
TestX1
(x-load)
18.00A18.00A1.00A0.00A0.00A192w /
162w
84.37%50.7°C /
50.7°C
0.0°C
3.32v5.01v12.08v5.05v-11.81v
TestX2
(x-load)
 1.00A 1.00A 70.50A0.00A 0.00A917w /
848w
92.47%51.6°C /
58.2°C
6.6°C
3.32v5.03v11.92v5.04v-12.10v
TMax1
(Max)
 20.00A20.00A74.00A5.00A1.00A1199w /
1081w
90.15%50.1°C /
58.8°C
 8.7°C
3.25v4.95v11.80v4.89v-11.60v


To reiterate what has already been said over on the previous page, the HX850 manages excellent voltage stability on all rails across all loads. The highlight of the testing however has to be the fact that the HX850 was able to pump out a huge 1081w, 231w more power than what was written on the box.

You may also wonder about the validity of the delta temperatures shown above. Well let me tell you right now that this PSU is so efficient that it was almost impossible to take a snapshot of in/out temperature readings where the unit was actually contributing anything to the 50c hot box temperature. Furthermore, when the PSU was operated outside of the hot box, the fan didn't spin up in the first instance until the load had reached 850w! On subsequent tests once the unit had warmed up a bit more, it did kick in at lower load levels, but appeared to be entirely based on temperature rather than load.

Corsair HX850 Scope Results @ 50c
  +3.3v +5.0v +12v
Test1
(25%)
Corsair PSU newCorsair PSU newCorsair PSU new
Test2
(50%)
Corsair PSU newCorsair PSU newCorsair PSU new
Test3
(75%)
Corsair PSU newCorsair PSU newCorsair PSU new
Test4
(100%)
Corsair PSU newCorsair PSU newCorsair PSU new
TestX1
(x-load)
Corsair PSU newCorsair PSU newCorsair PSU new
TestX2
(x-load)
Corsair PSU newCorsair PSU newCorsair PSU new
TMax1
(MAX)
Corsair PSU newCorsair PSU newCorsair PSU new

 

For the last part of the testing I analysed the ripple on the +3.3, +5 and +12v rails using a Rigol 25Mhz 400MSa/s oscilloscope. All readings were taken while the HX850W was installed inside the 50°C hot box to provide us with worst case scenario results.

The ripple suppression on Corsair PSU's has always been good, so good that there really isn't much between this HX850 V1 & the V2. The only way to distinguish between the two is the ripple on the +3.3v and +5.0v rails on the newer model is slightly better, but the older model actually wins on the +12v rail tests by 8.0mV on the 100% load and 12.0mV on the max load tests. Ripple suppression can be effected when pushing for that extra efficiency rating but these results are still so below the 120mV ATX standard that its far from anything to worry about.

Now lets move on to the conclusion and for TTL's Video.



Corsair HX850 V2 Power Supply Review Page: 5

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Conclusion

So when we reviewed the V1 PSU a crazy 3 years ago in 2009 we said that the HX series seemed to only get better with age. 3 years later will that statement still hold up? Well its a hard one because for the price the original was awesome and that's the reason why we adorned it with our best in class award which at the time was our highest possible award (above gold).

With the v2 Corsair have basically added a bit of spit and polish to what was already a great PSU. Its now got a Gold efficiency rating which to be frank the V1 was capable of in our original review so the main change in our eyes is the semi passive cooling. Corsair state that the fan will gradually spin up from the point when the unit is put under 170W of load, the thing is on our first set of tests we didn't manage to get the fan to budge until the unit was pulling 850w from the wall! Once we had tested it in our 50C hot box we tested again and this had dropped to around 500W which left us thinking that the fan speed is more closely linked to temperature than load (which is what it should be really but there are no official temperature limits or speed tables for us to quote from)

So now its time should you wish to take a look at TTL's video and also below that his thoughts on the aesthetics of the unit.



We did hope when we first heard about the V2 that Corsair would be rolling out the tapered edges and customisable fan surround that we recently saw on the GS line to the rest of the PSU's in their line up. Sadly not and considering that a great number of Corsairs new products have these customising options we think this is something they have missed out on. Especially with a unit that looks so similar to the old. Maybe it is just a minor revamp of the internals? You can buy individually braided cable kits to replace the modular cables which is a brilliant option but slightly hindered by the fact you still have some cables fixed to the unit. What also does not help is the cables fixed to the unit have normal multi coloured wires beneath some average braid. We understand that soldering all black cables inside a PSU could be tricky but we are sure a jig could be made up to make this possible. It would just add that extra feel of quality and remove the dated looking coloured cables, you only need to look at the modular cables which have all black wires inside just how different they look. The black cables blend into the braid like a stealth bomber blends into the sky for a radar. This is just another factor that makes us think this is just a minor revamp and not an all out overhaul.

To recap though the V1 was a class leader at the time, technology has moved on but so have prices. Corsair say the V2 will be retailing at the same price that the V1 is currently (£120) so it is still a very well priced unit that performs up their with the very best units in this price range and coupled with its 7 year warranty and Platinum specification efficiency it thoroughly deserves our OC3D Gold award. Quite a crazy price when if you consider the original HX620W PSU first retailed at £96 and only had 83% efficiency! The only reason we would upgrade to the AX850 would be if you wanted a fully modular unit, with all black cables and the possibility of being able to buy the replacement coloured cable kits. So the only reason to upgrade would be because of aesthetics. That is why if Corsair had of fixed those coloured wires on the fixed cables this unit could of been another class leader, sadly this time it just missed out.

So congratulations to Corsair for the HX850 which is still gold worthy meaning even 3 years later they have a power supply that is still giving the competition a headache!

    

Thanks to Corsair for the unit on test today, you can discuss your thoughts in the OC3D forums.