3rd or 4th 7970 worth it? Running Eyefinity

[Arr0way]

Hi All,

I am running 3240x1920 Eyefinity with 2 x 7970 Sapphire OC edition @ 1150 core, tbh I get half decent performance at this resolution.

My question is how much more would I get out of adding a 3rd card or a 4th... 7970 ?

Note, if I add a 3rd I would have to either buy a new motherboard (PCIe spacing) or water cool, if I buy a 4th i would need to buy a new board and water cool.

My other concern is that I've seen a lot of games, crysis 3, tomb raider etc max out my VRAM (use all 3Gb) in game using higher settings - probably due to the higher resolution.

If anyone knows of a benchmark for adding a 3rd and then 4th AMD card that would be great.

Processor is a i7 3770k @ 4.6Ghz on a Gigabyte Z77X-D3H mobo.

Cheers

 

[MeMeMeMe]

I have no experience of running tri-or quad-fire, but I'm surprised your performance is only half decent. I'm running pretty much the same resolution and same cards, and am pretty happy with them.

Maybe you are affected by the crossfire+eyefinity frame pacing issue. it's probably worth waiting a month or so till the amd driver which fixes this is (hopefully) released.

 

[Drangueos]

I'm running 2x 7950s with a [email protected] and a Sabertooth Z77 (almost the same as you)
Once I tested 3x crossfire.. it worked but I was expecting more... probably the 3770k was bottlenecking the 3rd card a little bit plus the 3rd slot was running at pci 2.0 and 4x... I think your 3rd slot will run at 4x as well.

If you need a little bit more power, probably it is gonna help a little bit, but don't expect too much... maybe around 25%, with an I7 3930k or better (6cores/12threads) it will scale better.

About 4 way crossfire, I wouldn't do it, because 4x doesn't scale very well and to get the best out of a 4 way crossfire you will need an I7 3930k or better (6cores/12threads), on your 3770k you can forget about it.

In my opinion I would sell your cards and go for 2 R9 290s, probably I will do that when they release the non-reference coolers...
Also you need to remember that your cards uses 2.5 slots and from the middle pci-e slot to the bottom one, on your MB, it is only 2 slots

 

[Arr0way]

Ok, with the reference cooler the 290 would only use 2 slots though right? Overspill is with non ref coolers?

I am toying with the idea of 2 3 or 4 290s now, it would mean a new motherboard & water cooling (when OC get the water blocks back in stock).

I will open another thread asking people if they think a 3770k @ 4.6 will bottleneck 4 290s.

Thanks