# Corsair AX850 850 W



## crmaris (May 6, 2011)

Corsair's AX850 is an 80Plus Gold certified 850 watt power supply that aims to be the highest-quality model in its segment. It is fully modular and shows excellent performance characteristics in our demanding test suite. With a price of $180 it is not cheap but quality has its price.

*Show full review*


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## ERazer (May 9, 2011)

Great review! 

definitely my next PSU


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## n-ster (May 9, 2011)

I really would expect much better voltage regulation than that.... Hope Corsair doesn't start slipping there!

but great efficiency marks


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## melkhior (May 9, 2011)

Very great PSU. My girlfriend has it and it's incredible. What I like more is that is almost silent even with the computer using furmark + LinX.

She's very happy with that PSU.

Ah, like always, great review


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## LAN_deRf_HA (May 9, 2011)

After you do the AX1200 think you could get your hands on a silverstone ST1200-G? Be nice to have all the gold, fully modular, 1200w supplies done under the same reviewer.


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## n-ster (May 9, 2011)

The AX1200 I would be interested in seeing.


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## crmaris (May 9, 2011)

I have reviewed it in the past but I will ask it again for TPU and stress it even more 

From the Silverstone Gold ones I have reviewed the smaller 750 but I will ask for the 1200 too.


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## Makaveli (May 10, 2011)

I just bought the AX750 this weekend its an outstanding PSU. And super quiet I wasn't sure the thing was on when I first powered it on.

If you can afford it MUST BUY!!!


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## null object (May 11, 2011)

Beware - you will not be able to power the 24pin, 2x8pin on the motherboard and running 2 video cards with 4x6pin directly from the power supply. You will need some kind of splitter.

I emailed Corsair about this and this is their reply:

Hello Nathan,
You will need an adapter something like this, LOGISYS AD202 12V Molex to 8pin P8 Adapter so you can run you 2 VCs and the 2 8pin 12V EPS on your MB. Thanks

Nothing in any review has touched on this.

This response directly contradicts Corsairs documentation stating "Only use Cables supplied"

Does the reviewer have any input on this?

I am trying to be positive and helpful. This is a great power supply and totally silent but this problem above bugs me as it is not documented anywhere.


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## mlee49 (May 11, 2011)

What? Why would you not be able to connect two video cards, an ATX motherboard, and dual 8 pin's for the cpu?

Do you have this setup? What exact setup do you have?


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## null object (May 11, 2011)

mlee49 said:


> What? Why would you not be able to connect two video cards, an ATX motherboard, and dual 8 pin's for the cpu?
> 
> Do you have this setup? What exact setup do you have?




I have a MSI Big Bang Xpower motherboard (2x8pin 12V EPS) 
I am not running power to the 6 pin PCIe power socket located near slot 1.






and two Gigabyte 460GTX (2x6pin each)





As you can see above Corsair admitted the cabling supplied would not support this setup and I would need an adapter.

I can wire it all up with adapter but the idea is to minimize the amount of cabling from the power supply - the whole idea of a modular design.

The AX1200 (Bigger Brother power Supply) fixes this by giving (I think) another 2 sockets for PCIe.

I would have taken a photo but it was late and my batteries were flat in the camera at time of install.


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## null object (May 11, 2011)

Also there is no description on the cables or where they are to go in any paperwork or box graphics.
It only states what plugs are at the end of the cables. It does not clarify where exactly you plug a particular cable in on the power supply.

It seem logical enough to think any trained monkey could figure it out easy enough but when you look at the sockets on the power supply VS the cables supplied it gets a bit harder??

Maybe I got a box full of incorrect cables but as there is no clear definition of what cables are supplied (Power supply socket end) I have nothing to reference.

Edit:

Just to clarify this - the 2x8 pin 12v EPS cable does not have 2x8 plugs on the other end which plugs into the power supply. I can't remember exactly what it has maybe a (12 pin?) but it goes to a plug which has 4 pins left empty.


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## mlee49 (May 11, 2011)

null object said:


> I have a MSI Big Bang Xpower motherboard (2x8pin 12V EPS)
> I am not running power to the 6 pin PCIe power socket located near slot 1.
> http://www.pureoverclock.com/images/review/motherboards/msi_x58bbxp/msi_x58bbxp_9.jpg
> 
> ...



Considering the additional mainboard power connection for PCI devices are rare(and often MOLEX) I would think MSI would have supplied the necessary adapters. Sounds like they provide a niche device along with 6 PCIE connectors it only seems logical that the mainboard manufacture would address this issue in either design of the board or with design of the power connections. 
Sorry but I dont think Corsair is remotely responsible to outfit every power supply to fit any and all mainboard designs, even if they are claiming "Only use Cables supplied"


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## crmaris (May 11, 2011)

null object said:


> Beware - you will not be able to power the 24pin, 2x8pin on the motherboard and running 2 video cards with 4x6pin directly from the power supply. You will need some kind of splitter.
> 
> I emailed Corsair about this and this is their reply:
> 
> ...



Yes you are right. In order to use the second EPS connector you have to sacrifice one PCIe cable (with two connectors on it) since the EPS cable is connected in the same place/connector with the PCIe one on the modular PCB.

Now why Seasonic/Corsair chose not to give two EPS connectors along with 4 PCIe. Well lets do the math, two EPS connectors can give approximately 2*300W=600W. 4 PCIe (8pin) can give 4*150=600W. Well we have 1200W in total (at worst case scenario) and only 850W max capacity,  so they chose not to make available all above connectors at the same time. 

However you can use some Molex to PCIe connectors with no problem since with your system you will not draw so much power.


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## null object (May 11, 2011)

mlee49 said:


> Sorry but I dont think Corsair is remotely responsible to outfit every power supply to fit any and all mainboard designs, even if they are claiming "Only use Cables supplied"



That is fair but they do have a responsibility to alert the purchaser of the limitations of the product - and to a lesser/greater degree reviewers should also.

I am keeping my power supply for now - It is a great power supply but if I was not able to get around this problem myself it would be back to the shop for this one.

My complaint is that I was not able to know this limitation until I had opened the box and semi installed the product. That is Lame I think.

So that's all people reading this.... beware of this limitation or make all your own cables up or something.


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## n-ster (May 11, 2011)

null object said:


> That is fair but they do have a responsibility to alert the purchaser of the limitations of the product - and to a lesser/greater degree reviewers should also.
> 
> I am keeping my power supply for now - It is a great power supply but if I was not able to get around this problem myself it would be back to the shop for this one.
> 
> ...



Am I wrong to assume that with most of the other modular 850W PSUs, you cannot run your setup either? or at least 90%+ of them can't? in which case Corsair shouldn't be blamed for this.

The motherboard you have is almost exclusively used for very high power users (1KW+), so is designed as such. I do not blame the Motherboard nor the PSU maker, and I do not blame you either. IMO it just is, stuff like that happens.

But I'm trying to understand, the PCI-E connectors and the 8 Pin for mobo connectors have the same plug on the PSU end right? *I actually don't understand atm lol, trying to make sense out of it* Yea this sucks, but if there is ANYONE to blame, it is the mobo not warning you that most common mid-high power PSU's won't run it because of the connectors.


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## mlee49 (May 11, 2011)

null object said:


> That is fair but they do have a responsibility to alert the purchaser of the limitations of the product - and to a lesser/greater degree reviewers should also.
> 
> I am keeping my power supply for now - It is a great power supply but if I was not able to get around this problem myself it would be back to the shop for this one.
> 
> ...



Honestly, I think you should have known about this prior to purchasing the power supply; that is if you researched your motherboard prior to purchase.

It's your responsibility to ensure compatibility, Corsair can only guide you. Yet their claim of 'completeness in a bag'(new term  ) covers about 98% of all configurations.

It sucks that you think the power supply has 'limitations' when its more of an issue of compatibility.


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## extrasalty (May 12, 2011)

Very good proper review- this is right up there on the level of [H] and johnyguru. Keep up the good work and throw some more O-scope shots for different loads.


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## wiak (May 12, 2011)

nice review, clean and informative
i love my HX 620W so gonna get an AX 850W when i upgrade my PC later this summer ;D


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## LAN_deRf_HA (May 12, 2011)

So the 6 pin is to aid with powering the pci-e slots when fully loaded, and the extra 8pin is for extreme processor clocking? I'm curious if there's an actual instance where that would ever be needed, as SB has a pretty universal multiplier wall that I'd expect would hold you back before you'd ever draw that much power.


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## dr emulator (madmax) (Jun 18, 2011)

i've just had to rma my ax 850 w  why ? 

well i think my gigabyte motherboard has some kind of a electronic fault on it ,because it failed an overclock then made the powersupply go pop ,which then wouldn't work for about 16 mins after switching it on at the wall , but i beleive it was the motherboard that did that 

another thing to think of is the eps cables are quite short ,i'm not sure how short but they only just fitted in my coolermaster cm690 II (very tight squeeze)

i was going to order a new 1 for my old system (sort of a spare) but my usual shop (scan.co.uk) hasn't any in for over a week  (they are the cheapest for this version of powersupply in the uk )


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## newtekie1 (Jun 18, 2011)

null object said:


> That is fair but they do have a responsibility to alert the purchaser of the limitations of the product - and to a lesser/greater degree reviewers should also.
> 
> I am keeping my power supply for now - It is a great power supply but if I was not able to get around this problem myself it would be back to the shop for this one.
> 
> ...



The second EPS connector on that board is not necessary, AFAIK.  It is only there for when you are doing extreme CPU overclocking, and you aren't going to be using an 800w PSU with 2 graphics cards when doing that.

The setup isn't supported because the power supply isn't rated to handle that setup.  If all of those connectors are in use, and actually necessary, then the PSU will be overloaded.  So don't plug in the second EPS connector and you will be fine.


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