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Crossfire question

post #1 of 6
Thread Starter 
Ok so I sold my 5970 to a friend and picked up 2 6970s and xfired them and it's a great performance boost but as I was starting to over clock I noticed that I my motherboard is 16x by 4x pci express now I'm going to order a new board but I'm wondering how much performance and I'm losing having them run 16x by 4x?
post #2 of 6
You're loosing some performance. 16x-4x is only useable for the MainGPU - PhysXGPU concept, not for CF/SLi.
The first card has too much bandwidth it can't use, the second one is hugely bottlenecked.
Get at least 8x-8x
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post #3 of 6
not according to the most recent findings...I think they ran a 6990 on a 4x (comparable to 6970's on 2x slots) slot and it only gave up 2% fps to a 16x slot
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post #4 of 6
Not as much as you would think, but you are losing some performance. I would spring for a board with at least 8x8x and the loss will basically be unnoticeable compared to 16x16x. 16x and 4x will cause somewhat of a bottleneck on second card though.

Heres a link that may help somewhat.

http://www.techpowerup.com/reviews/A...caling/25.html
Edited by Chuckclc - 4/14/11 at 1:52am
post #5 of 6
Thread Starter 
Well I'm thinking of getting a Asus crosshair mobo and just running the 6970s at 16x by 16x and calling it a day but if I'm not going to gain noticeable performance then I might just wait until I upgrade the cards again
post #6 of 6
The ASUS Crosshair IV Formula is a great board, I had it before.

However, bear in mind you'll still have some bottleneck on that 1090T, I've had a X6 1055T @ 4.1Ghz with my x2 6970's and I still had some bottleneck.

If you want to unleash the rough power of those cards, I'd suggest upgrading to the Sandy Bridge route

If not, that Crosshair IV Formula will serve you quite well, I had it on my hands, great motherboard! Definitely recommend it!
    
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