I'm taking the plunge

Mario Balotelli · 10 Oct 2011 at 19:53

In all seriousness, I was always going to, I just harboured a few concerns which I felt were worthy of wider discussion given the potential consequences of such a scenario proving a reality. I still believe there remains a threat, however slight, I've just learnt to accept it - particularly due to wanting a PC no less...

Meh.

Anyway, I'm getting all my parts together for my first ever build. And I'd greatly welcome a little feedback..

I've already managed to sort myself a case, a Cooler Master Cosmos S courtesy of a good pal of mine, and I've gathered most of the essential, key components already.

Motherboard: P8 Z68-V PRO
GPU: 1* Asus GTX 580 Direct CU II
CPU: I7 2600K
PSU: Corsair AX850

Now the main reason I started this thread, was essentially as I'm considering buying another GTX 580 and running an SLI set-up.

I've read varying opinions on what is sufficient enough to run such a set-up over the past few days, PSUs Motherboards etc.

But specifically, in my case, would a PSU as highly efficient as a Corsair AX850 manage a GTX 580 SLI set-up? Is it really necessary to have a 1000w PSU to run a pair of GTX 580s in SLI, as is often mooted online?

I've also read that SLI set-ups on a P8 Z68-V Pro aren't recommended as they're not ideally suited for such strenuous multitasking, is there any truth to this?

I'm not too sure where I stand here. Any help would be appreciated.

Cheers.

stulid · 10 Oct 2011 at 20:06

A 850w PSU is fine for a GTX580 SLI setup.

The P8 Z68-V PRO board does SLI at 8X/8X just like all good boards should, so you get equal bandwidth to both cards, if you are wondering about getting 16X/16X? then dont bother, the motherboards that do this are £200+ and Hardocp have conducted a test of SLi at 16X/16X vs 8X/8X and the difference was very minimal.

I've also read that SLI set-ups on a P8 Z68-V Pro aren't recommended as they're not ideally suited for such strenuous multitasking, is there any truth to this?

Rubbish.

olivier renault · 10 Oct 2011 at 20:16

Efficiency doesn't have much to do with being able to power a big rig, although an efficient PSU will heat up less (since wasted energy gets converted into heat). I would say yes for a good 850W. I would take a AX850 over, say a OCZ ZX 1000W. Mainly a personal choice.

I am getting a Seasonic X-850 for my next rig, and this PSU is over-specced (can pull over 1000W). The Corsair, IIRC, is based on the same design. Given the price difference between a AX850 and a Seasonic, the choice is clear!

I would recommend a good quality PSU with couple of 580's. No point getting something that will be a liability. Antec, Enermax, Corsair.

As for the motherboard, I'm can't say for sure, but the AsRock Z68 Gen3 has some extra power for the PCIE. But I'm sure a P8Z68-V Pro (which BTW is practically the same board as the P8Z68-V, down to the VRM design and Bluetooth support) will be more than adequate.

stulid · 10 Oct 2011 at 20:20

olivier renault said:
I am getting a Seasonic X-850 for my next rig,

Whats that little beauty setting you back?

Mario Balotelli · 10 Oct 2011 at 20:20

stulid said:
A 850w PSU is fine for a GTX580 SLI setup.

The P8 Z68-V PRO board does SLI at 8X/8X just like all good boards should, so you get equal bandwidth to both cards, if you are wondering about getting 16X/16X? then dont bother, the motherboards that do this are £200+ and Hardocp have conducted a test of SLi at 16X/16X vs 8X/8X and the difference was very minimal.

Rubbish.

Thanks mate.

Would it be pushing it though? Would the system run as smoothly as you'd expect under the load of a sole GPU?

Surely there'd be a difference though? Hypothetically, let's imagine I ran the above set-up with an ax850w and an identical system with an 1000w+, what would be the differences between the two?

Would it effect the stability of your overclock for example, leading you with no option but to bring it down to compensate...?

Mario Balotelli · 10 Oct 2011 at 20:24

olivier renault said:
Efficiency doesn't have much to do with being able to power a big rig, although an efficient PSU will heat up less (since wasted energy gets converted into heat). I would say yes for a good 850W. I would take a AX850 over, say a OCZ ZX 1000W. Mainly a personal choice.

I am getting a Seasonic X-850 for my next rig, and this PSU is over-specced (can pull over 1000W). The Corsair, IIRC, is based on the same design. Given the price difference between a AX850 and a Seasonic, the choice is clear!

I would recommend a good quality PSU with couple of 580's. No point getting something that will be a liability. Antec, Enermax, Corsair.

As for the motherboard, I'm can't say for sure, but the AsRock Z68 Gen3 has some extra power for the PCIE. But I'm sure a P8Z68-V Pro (which BTW is practically the same board as the P8Z68-V, down to the VRM design and Bluetooth support) will be more than adequate.

Thanks for the input mate.

Why is it some common to hear such claims though?

Frequently you'll hear of 'nothing but a 1000w will suffice' etc etc, simply ignorance?

stulid · 10 Oct 2011 at 20:25

A PSU is best run at around 60%-70% for best efficiency

A older more power hungry socket 1366 i7 test system used this (complete system power draw from the wall socket) with a pair of these cards - http://www.guru3d.com/article/geforce-gtx-580-sli-review/14 - a Sandybridge system will and does use less power.

If you were considering a GTX480 SLI setup, then a 1000W PSU would be what I would have said.

panyan · 10 Oct 2011 at 20:28

stulid said:
A PSU is best run at around 60-70% for best efficiency

that graph peaks about 55% by my eye

stulid · 10 Oct 2011 at 20:31

panyan said:
that graph peaks about 55% by my eye

I actually typed that before I dug the graph up from the photobucket.

Mario Balotelli · 10 Oct 2011 at 20:34

If could ask, in an ideal world, what PSU requirements would you place to run such a set-up?

Scougar · 10 Oct 2011 at 20:36

"Based on" and "the same" does not mean you get the same performance. Be careful. Any decent quality 850W PSU will suffice, but there are some good recommendations in here already :-)

Mario Balotelli · 10 Oct 2011 at 20:37

stulid said:
A PSU is best run at around 60%-70% for best efficiency

A older more power hungry socket 1366 i7 test system used this (complete system power draw from the wall socket) with a pair of these cards - http://www.guru3d.com/article/geforce-gtx-580-sli-review/14 - a Sandybridge system will and does use less power.

If you were considering a GTX480 SLI setup, then a 1000W PSU would be what I would have said.

Surely though a pair of vastly more powerful 580s would require the greater workload from a PSU?

stulid · 10 Oct 2011 at 20:37

Mario Balotelli said:
If could ask, in an ideal world, what PSU requirements would you place to run such a set-up?

850W, a good one like Olivier mentioned (Corsair/Antec etc) you can find tests online of the power consumption of GTX580 SLI, but these all use the older i7 1366 test systems.

Mario Balotelli · 10 Oct 2011 at 20:41

Fair enough. So I take it no-one would consider it worthwhile returning an 850w and then paying that little bit more for a 1000w PSU, under these circumstances?

stulid · 10 Oct 2011 at 20:43

Mario Balotelli said:
Surely though a pair of vastly more powerful 580s would require the greater workload from a PSU?

They got a average use of 522W, the full stress (719W) is done using Furmark which pushes the complete (CPU+GPU) system to the maximum which is never achieved during gaming.

If you assume a Gold rated PSU is say 90% efficient (rounding up) then that means its pumping out 469.8W, which is over 50% of a 850W PSU

olivier renault · 10 Oct 2011 at 20:51

stulid said:
Whats that little beauty setting you back?

£165

stulid · 10 Oct 2011 at 20:52

olivier renault said:
£165

Thats actually a really good price for the quality you are getting.

olivier renault · 10 Oct 2011 at 20:56

Mario Balotelli said:
Thanks for the input mate.

Why is it some common to hear such claims though?

Frequently you'll hear of 'nothing but a 1000w will suffice' etc etc, simply ignorance?

It depends really. If you go full water rig with loads of fans and pumps, drives, massive enthusiast overclocks, 6 core Intel, a Enermax / Antec / Corsair 1000W would be a good buy. Then again, if you go water, you can afford power (meaning £200 PSU).

For a enthusiast home rig on air, with usable overclock where you wont cook your chip or GPUs, 850W will be enough.

The SandyBridge chips are very efficient, low voltage CPUs as well. They are 95W CPUs, more of course if you overclock.

olivier renault · 10 Oct 2011 at 20:58

stulid said:
Thats actually a really good price for the quality you are getting.

yup. Fully black sleeved, virtually silent, super efficient, great build quality. It pays shopping around. Not in stock, I bet they wont get in stock in a hurry, but I'm not stressed. I've got another PSU in the meanwhile for a single 6950.

BTW, those AX850, X-850 can pull a lot more than 850W if needs be. But if it comes to that, you wouldn't want to run those for extended periods unless you are made of electricity.

Mario Balotelli · 10 Oct 2011 at 21:11

Thanks for the input everyone, greatly appreciated.

Re the motherboard query, is that a potential issue?

I know there are motherboards more suited to using SLI technology, but how would the p8 z68-v pro fare in comparison?

For example, I saw this quite recently, salesman pushing potential customers towards the more expensive platform or is there some truth to the "cut off" claim?

14:35 onwards

http://www.youtube.com/watch?v=VTsEOIyqXtg