MSI P55-GD80 & crossfire issues

[p1987]

I borrowed an MSI r6950 twin frozor 2 graphics card and tested it with an additional one on my P55 motherboard. I noticed a drop in fps in Battlefield 3 or no improvement on my frames what so ever?

I understand that crossfire doesn't always "improve" game fps, but it wouldn't have been worth me spending the additional £150 for another one.

Can anyone shed any light on this please?

Note: i did run a BF3 gpu and cpu balance test. It looked like my CPU was bottlenecking my GPU? ? impossible right?

My specs are as follows

Intel core I5 750 @ 3.00ghz
XFX PRO 750w
MSI P55 GD-80 motherboard
8gb corsair red vengence memory

Windows 7 64bit with the latest drivers from windows update.

19" wide screen dell monitor

Note: I have tested this on a 24" monitor in Crossfire with the same specified low fps results.

Regards.

 

[jamesriley94]

You saying you're running 3 6950s?

If so, anything above 2 graphics cards doesn't really provide any improvement in framterates, and can even make it worse sometimes.

The CPU shouldn't really be bottlenecking, but it is possible.

 

[p1987]

No only 2 6950's.

I've only borrowed it to test an additional 6950. Its really strange that they lower the fps.

Does anyone have any experience with my motherboard?

 

[Master&Puppet]

Well your mobo should be fine with it looking at the specs. 2 x8 pcie lanes are available. Have you got the cards in the right slots for a start?

Have you downloaded catalyst application profiles from here http://sites.amd.com/us/game/downloads/pages/crossfirex-app-profiles.aspx
(This creates driver profiles specifically for xf gaming)

Have you got an HWM with on screen display to show that the GPU usage on both cards and see if they are both spinning up? You can also check for CPU usage to see if that is bottlenecking but I doubt it.

Other things I can think of - make sure you don't have youtube or anything similar open at the same time (Flash throttles GPU clock when it's running in the background).

Test for an increase in FPS on the singlepalyer game not online. I have a 3570K and 2x 7950s all heavily overclocked under water and in multiplayer my fps drops to 30-40 quite regularly because of network connection speed. If you haven't got an HWM showing CPU & GPU use when this happens then it is quite easy to think that your hardware is bottlenecking when infact the GPUs/CPU are working at 50% and the FPS is low because the system is waiting for data from the servers.

Hope some of that helps!
M&P