• Competitor rules

    Please remember that any mention of competitors, hinting at competitors or offering to provide details of competitors will result in an account suspension. The full rules can be found under the 'Terms and Rules' link in the bottom right corner of your screen. Just don't mention competitors in any way, shape or form and you'll be OK.

PSU for 3 7970's

ChrisLandin

ChrisLandin

ChrisLandin

Associate
Joined
10 Jun 2009
Posts
2,225
Location
Darlington
Hey guys.

Ive picked up a cheap 7970 and I fancy xfiring it with my other 2 7970's.
Currently I'm running an xfx 850w psu with no issues but what size wattage would I be looking for the 3 gpu's.

Any recommendations on brand also would be great, I'm miles behind in the current game of tech
 
You're looking at nearly 600W for the tri 7970's at stock, with the rest of your system in mind something like 760W, light OC CPU_GPUs will easily push your system towards 810W. Those like myself with multiple GPUs usually stay with light OC because we already have enough grunt and to keep temps down.

Agree with fx63007850, but also worth considering the SuperFlower Leadex Platinum 1000W Fully Modular "80 Plus Platinum" (black or white versions) that comes highly rated and currently on TWO with 5 year warranty. Unlike the EVGA G2 the PCIE cables (both are enough for 3 GPUs max) aren't too long and the PSU is silent.

https://www.overclockers.co.uk/showproduct.php?prodid=CA-006-SF

I have a 1200W Platinum PSU powering two 980 TI's, etc and it's silent with hard OCs reach near 830W, not too clever to run near PSU limits but SuperFlower PSUs are over engineered and the 1000W Platinum is capable of 1123W tops.

The difference between EVGA G2's Gold and SF 1KW Platinum is 2-3% efficiency, not worth worrying about.
 
I offered you a quality powerful Psu in your wanted thread which would've been ideal for you're wanting to power. One thing I never do is cut corners on Psu's. Better over kill than borderline.
 
Geeman1979 said:
I offered you a quality powerful Psu in your wanted thread which would've been ideal for you're wanting to power. One thing I never do is cut corners on Psu's. Better over kill than borderline.
Click to expand...

Yes you did mate and I truly appreciate the reply but a 1300w psu would be overkill for my needs and probably outta my price range too.
 
ChrisLandin said:
Yes you did mate and I truly appreciate the reply but a 1300w psu would be overkill for my needs and probably outta my price range too.
Click to expand...


Overkill? Not really in all cases. I used to draw over 1300w after conversion during benching with a hexacore and required cooling. These are still 300w gpu at max. That's 900w theoretical at max then add your cpu. That said under normal circumstances I'd guesstimate for most users draw would be around 800w to 1kw after conversion depending on load.
 
What 1000W Corsair were you looking at? Bear in mind they are generally overpriced for what you get, prime example is the RM1000 for which you can usually get the XFX Pro 1050W, EVGA G2/GS 1050W for the same price which are all better units
 
Paradiso said:
I run 2 x 7990's (equiv to 4 x 7970's) and a xeon 5650 @ 4GHz on a 1200W Corsair so a 900-1000W should be fine.
Click to expand...

Do u play bf4? How do u avoid stutter? I have a 7990 and a 7970 and find adding the extra card makes the experience worse.

Also have u managed to get vsr working on latest drivers. Mine enables but shows no further display options
 
I ran 1x7970+1x7990 on an x58 platform for ages. Corsair Link went as high as 900W or so output for the lot.

Your CPU uses less but is overclocked, and two 7970s would use more power than a 7990 (which are binned for low power).

I'd say you want a minimum of a 1000W PSU.

I got far worse experience playing games with all three GPUs than just two however. The whole setup was horrible and I'd not really recommend it.

XDMA crossfire is supposed to be much better.
 
rtho782 said:
I ran 1x7970+1x7990 on an x58 platform for ages. Corsair Link went as high as 900W or so output for the lot.

Your CPU uses less but is overclocked, and two 7970s would use more power than a 7990 (which are binned for low power).

I'd say you want a minimum of a 1000W PSU.

I got far worse experience playing games with all three GPUs than just two however. The whole setup was horrible and I'd not really recommend it.

XDMA crossfire is supposed to be much better.
Click to expand...

Kinda mirrors my experience with 7990 + 7970. Wonder if it would come into its own though when dx12 split frame rendering comes out though. The current AFR is garbage.
 
The old crossfire bridge was limited in bandwidth, meaning that even when AMD "fixed" the microstutter issues they only were able to up to 1600p60.

1440p144 was out of luck, as was any 4k resolution.

I'm of the opinion that 1600p60 was out of luck with more than 2 cards (as need to send more data, from/to 2 slave cards) as it never really got fixed for me even using my Dell 3007WFP (which is 1600p60).

I initially went to a single 980 and had a much better experience than the trifire setup even if bench scores were lower. That's not to say it's an nVidia thing - I remain convinced a single 290x would also have been a better experience.

How much are you paying for the 7970, and a new PSU? If you were to take that money, and sell your other two, you might easily find yourself with a single 970/980 or a 390x.

Hell, if you're about to pay say, £70 for a 7970, and £85 for a decent 1kW PSU, and instead you sell the current two 7970s for £140 total, putting all that cash together you have about £300. Definitely enough for a decent upgrade.
 
I paid £65 for the card with the block included.

I'm thinking I might just stop with what I have for now if I'm honest. To be fair I have no issues with games I play its just mainly I always wanted to try tri fire and it was a decent oppourtunity to do so but I obviously didn't think it through very well.

I looked into getting a mobo for my 3770k that would do 3 cards and the prices now are horrendous.

So I might save up some cash and go x99 or skylake.
 
You must log in or register to reply here.
Back
Top Bottom