what 750+ w psu to buy

[codnan]

I have to buy a new 750w PSU soon as I am running 2 7950s in crossfire on my 650w xfx xxx and I don't dare start over clocking either the GPUs or my CPU as I Think there is already too much stress on my PSU so am looking to buy a at least 750w PSU
It must have 4x8pin pcie plugs as my GPUs are sapphire 7950vapourx which each require 2x8pin pcie
I was just looking for recommendations as I don't want to really have a huge amount of money but don't want to risk my GPUs on a cheap PSU ,I have been looking at this one ...XFX Pro Series 750W XXX Edition Modular for £86 as I know the xfx ones are made by seasonic ,but if anyone has any good recommendations that are cheaper or better ?

[Willzzz]

You might be surprised how little power they take, average power consumption is probably around 350w which would be ideal. Even overclocked and stress tested 600w which is still within spec.

Your PSU is not cheap, even if you were to overload it, a quality PSU like that shouldn't damage your components.

What are the rest of your components? Are you able to test your actual power draw?

http://www.techpowerup.com/reviews/A...ssFire/22.html
http://www.techpowerup.com/reviews/S...apor-X/26.html

[Willzzz]

Overload test results:

http://www.hardwaresecrets.com/artic...-Review/1604/9

This PSU actually delivered over 750w when tested and shutdown cleanly when the maximum was exceeded.

[kalniel]

Yeah as above, no need to change PSU.

[Greybeard]

I'm inclined to agree on what has been suggested above. But if you plan to make some changes in your system, like overclocking or adding more hardware, you can always look at the Corsair TXM series. Prices are very reasonable with great quality.

[Kovoet]

Don't sell yourselves short, I have the AX850 with the white cables which you can get from corsair. Very stable

[codnan]

I know that my 650w is also made by seasonic ,and that the power draw off my whole system (including the 2x sapphire 7950s) should draw at most around 500w ,but I was still under the impression that you should have at least a 750w for crossfire 7950s
My system is .....
I5 2500k stock at the moment will be 4ghz
2 sapphire 7950 vapour x at 850mhz but will be activating boost (so 950mhz)
Xfx xxx 650w PSU (the older one with the green fan lol)
Gigabyte z68 mobo
2x4gb corsair dominator
1x HDD
5 fans (including CPU cooler)

[Willzzz]

Personally I wouldn't worry, you will running at under 75% the vast vast majority of time.

The older 650W model only has three 8 pin connectors, but you say you are using 4?

If you want to buy a 750W then yes another XFX would be a good buy, consider getting the Black edition though, more expensive but better and more efficient. Make it worth the hassle.

[codnan]

So you reckon 650w will be enough even with boost activated (on both cards) and my i5 over clocked to 4ghz

The older 650W model only has three 8 pin connectors,
Yep I know I just figured PSUs usually have 2 or 4 and I have 1 new vapourx with 8+8 and an older one with 6+8 so I need 3x8 and 1x6
.....

[Willzzz]

The older model does less well on the overload tests:
http://www.hardwaresecrets.com/artic...y-Review/899/8

However it shouldn't really be possible for your maximum draw to exceed the rated 650w.
But it's always nice to have a bigger safety margin for peace of mind.

As I said above, if you are going to upgrade I'd get a proper upgrade and invest in a gold rated power supply so you are getting a tangible benefit from your upgrade.

[speaker5]

I would get a corsair AX860, its platinum rated and even has a 7 year warranty from corsair. Being fully modular we can hope it's some what future proof.

[mysticmagic788]

If you dont mind non modular I would grab an 850w xfx. Most places have them at only a tenner difference to the 750w.