Recommend me an i7 SLI PSU please?

claypigeon101 · 31 Jan 2015 at 13:07

Hi guys,

I'm replacing my OCZ ZX 850W due to burning pins on the ATX motherboard connector... That's all sorted now and an RMA is coming but I'm going to stick it on the bay and get myself a brand new unit.

Specs are in my sig, but mainly I'll have
OC'd i7 2600k
2x GTX 580 SLI (for now- one 970 will go in ASAP)
4x4gb RAM
Corsair H100i/NZXT X61 cooler
2 SSDs, 1 or 2 HDDs
3 or 4 case fans

Do you think I need an 850W PSU? I've been told to go for Superflower or Seasonic. I'm aiming to get a 970 in (which will dramatically reduce the power draw) sometime before March but we'll see how it goes.

Can you recommend me a PSU that won't be overkill, but will be enough for my 2 580s? I understand the efficiency ratings tend to apply most when the PSU is putting out near max wattage so I'd like to bear that in mind also.

Thanks!

pastymuncher · 31 Jan 2015 at 17:30

A pair of 580's in Sli have a total system power draw of around 600-650w. Going by that figure 750w should be more than enough so I would normally suggest the excellent EVGA Supernova G2 750w. It's a quality unit built by Superflower and is based on their Leadex Gold platform but get's a whopping 10 year warranty. The only problem is that it's out of stock at the moment.

As a alternative how about the psu it's based on, the Superflower Leadex Gold 750w. For me personally I have a problem with this psu. The sockets that you plug the cables into have bright led's that can't be turned off and that would just annoy the hell out of me.

Another alternative is the Seasonic G series 750w. I have this psu and it's excellent. It's also very quiet. It's not fully modular but the fixed leads you will be using anyway as they are the 24 pin, 8 pin and a pair of dual pci-e leads. You may not like the ribbon cables for the modular leads though. I really like them as it's so easy to do cable management behing the mobo tray.

Whatever one you decide to go for is going to be decided by your current setup but will be overkill for a GTX970 (even a pair in Sli only have a total system draw of around 450w). At least you will have power to spare should you go for something more power hungry in the future.

ChugNorris · 31 Jan 2015 at 18:38

The 750w G2s will be back in stock late next week. The Superflower 750w Leadex is just as good though and personally i think the LEDs look great, but purely down to personal preference.

claypigeon101 · 2 Feb 2015 at 21:44

Thanks guys, I couldn't ask for a better response.

I have the NZXT S340 so my PSU is shrouded, the Superflower lights may just give a subtle white glow from beneath which might be great but I'll test it with a little torch first!

Are you guys sure that 750W is enough to run 2 GTX 580s with all my other gear?!

I'm RMAing my original PSU because of two bad 12V rails on the ATX connector... which I'm told could be too much power draw which could be related to my GPUs? And that was 850W not 750.

Also, what do you guys say to having more than one rail? I read a really interesting article on how you should have multiple rails especially if you have multiple graphics.

What is the rail arrangement on the three you've recommended, do you know?

Thanks

pastymuncher · 3 Feb 2015 at 10:01

Definately sure as I checked a load of reviews before I recommended the psu's. Both are single rail, the Superflower has a 749w 12v rail, the Seasonic 744w. Your ZX850 has a single 70A 12v rail not multiple rails.

There's another option now, the Superflower Golden Green 750w Modular. It has a slightly weaker 12v single rail of 726w but is still more than enough for your pc.

claypigeon101 · 3 Feb 2015 at 15:30

pastymuncher said:
Definately sure as I checked a load of reviews before I recommended the psu's.

Thanks pasty. Really appreciate you doing that.

I've been checking a couple of PSU calculators online and they said I need towards 900w... Don't know how reliable they are, especially when your experienced advice says I should be fine.

I'm still concerned about the rails, since I read an article about how the power should be distributed... but watching a video or two by everyone's favourite american Linus techtips my fears are mostly unfounded.

I do like the white Superflower since my case is white. But the EVGA cable sleeves and connections are all black and the SFs are odd colours like red or blue... why?! Hahah. Any benefit having the SF over the EVGA? 5 years extra warranty on the EV...

Also do you think it will run with poor efficiency once I get my 970 in? I read that the highest efficiency comes with the highest load.

My friend is building a 4770k OC/16gb/970 rig and I'm going to recommend to him the same PSU as the one I eventually decide on (thanks to your advice) too. Do you reckon that's a good idea?

pastymuncher · 3 Feb 2015 at 19:16

PSU calculators over estimate and none of them are very good anyway. I always check several reviews to see what systems actually pull before recommending something.

The EVGA is basically the same psu as the Superflower Leadex as Superflower builds it and it's based on their Leadex platform. I think about the only difference is the fan. The bonus of the EVGA is the extra warranty giving you a massive 10 years.

The EVGA seems to be most efficient between 298w and 418w (90.2%) so you will be fine when you go with the 970. There is a excellent review here and amongst other things he does efficiency tests at varying loads.

Stop worrying about the rails. A single rail is fine, they wouldn't build them else. These units are a higher quality than your OCZ too. This monstrous great thing has a single 1999.2w/166.6A 12v rail and can run quad cards with everything massively overclocked to death.

claypigeon101 · 4 Feb 2015 at 15:27

pastymuncher said:
A single rail is fine, they wouldn't build them else. These units are a higher quality than your OCZ too...

Thanks pasty. Really appreciate your input. Makes such a difference!

I will definitely go with the EV or the Super.
EDIT: Having said this the SF is down £15 to £84.95! Winner!

Can I ask one more question please. As I mentioned my friend is working on a 4770k/4x4GB/970 build and he needs a PSU. He's read all your advice and is just wondering, since he has a Corsair H100i with Link software, should he go for the Corsair 750i here? Will he get any benefit by having the link software across PSU and cooler.

The extra cash isn't an issue, and he'd be happy with the SF or the EV anyway. But is it worth the extra to have the Link compatibility? Bearing in mind his i7 is OCUK overclocked and he won't be messing with it further.

Thanks!

pastymuncher · 4 Feb 2015 at 19:11

As far as I can tell the Corsair link software is just another monitoring/tweaking tool and there is no benefit, performance or otherwise to keeping everything Corsair. As far as psu's go I don't think people should be fiddling with fan speeds etc anyway. I certainly wouldn't pay the price premium for this "feature". Your mate could easily go with the Superflower Leadex Gold 650w and still have power to spare if he dropped a second GTX970 in at a later date.

claypigeon101 · 4 Feb 2015 at 20:33

pastymuncher said:
...and still have power to spare if he dropped a second GTX970 in at a later date.

Sounds great pasty. Thanks again on this.

I'm sure he'll go for the 650 or 750 either way since they're on offer this week (OCUK read my mind?!)

And you're right, since the SF quality seems so good it seems pointless to have Corsair when the premium is for the 'digital' features.

As for me I'm going to go with the 750 with my 580 SLI for a short while. Hopefully by maybe March or April I can look to getting a 970 in there and drop the load anyway.
EDIT: The only negative point is the darn coloured connectors! What's up with that? I guess it's a quirk of the SF brand. Since that's the case I sort of don't mind it as much, I guess.

Thanks for everything, it really is appreciated.

pastymuncher · 5 Feb 2015 at 10:25

Yeah, I don't like the coloured connectors either. They always seem to have to "bling" things up. It's a shame really as they are cracking psu's but it's another reason I usually recommend the EVGA G2 over the Superflower version.