Why are my GPUs underperforming?

[IllogicalGlory]

(custom = extreme + full screen)

My setup is as follows:
7870 2gb (@ 3.0 x16) - I think in crossfire it only runs at x8 though, am I right?
7850 2gb (basically 7850 crossfire) (@3.0 x8)
i5 3570k (@4.2 GHz)
Corsair TX 750
Sandisk 32GB SSD

I'm told the proper FPS should be around 54 (http://www.youtube.com/watch?v=q3X-0JEM2ow), but mine is considerably lower. What could possibly be the reason for this?

 

[dudewitbow]

drivers? other than that, there is a minor difference between Unigine 3 and Unigine 4


and i caught one thing, his quality is set on high, yours is on Ultra

 

[JackNaylorPE]

You are using crossfire on two different (7870 + 7850) cards which though possible:

http://sites.amd.com/PublishingImages/Public/Graphic_Illustrations/WebBannerJPEG/AMD_CrossfireX_Chart_1618W.jpg

is not something I'd recommend.

I can't tell how good or bad it might be as I don't know what motherboard you have. Some MoBos advertised as CF compatible only have one x16 slot and one x4 slot

 

[IllogicalGlory]

My mobo is the ASRock extreme3 A77. It has a 3.0 @x16 and a 3.0 @x8, which should be fine from what I've heard.

 

[Airm3n-1292454]

Rule out your pci-e lanes they won't be the bottleneck. Even if they were pci-e 2.0 lanes it still wouldn't be the bottleneck.

 

[IllogicalGlory]

I updated the drivers to the current ones and reduced the quality to high. The results are unimpressive:

 

[dudewitbow]

have you installed the latest catalyst application profiles? if not, the only thing i can think of is uneven gpu loads. use a program and record the gpu workload while runing the benchmark. possibly one of your cards are not maxing out.

 

[IllogicalGlory]

Well, one of them does not max out because it has to slow itself down to match the slower one. The 7850 maxes out while the 7870 only goes up to about 80%, which I think is correct.