Crossfire Gigabyte 7970ghz No Fps Increase

[xxjonsyxx]

I crossfired the two cards, and no game is having increased fps from single card. The crossfire emblem appears in the games so I know crossfire is working. Disabled Ulps through afterburner and made sure by using regedit. GPU-Z says both cards are being used but one doesn't work as hard as the other. I doubt my 3570k @ 4.5ghz is bottlenecking. Tried In Farcry3, Battlefield 4, Dying Light.

 

[Sergeant_Sneaky]

Are the cards in 8x/16x pci slots? Xfire will work in 4x I believe but I'm sure it'd have a performance hit.

 

[xxjonsyxx]

Thank you for the response. The performance is the exact same or in same cases I get lower fps than I do with one card. GPU-z says they are running at 8x anyways so that is not the problem. I forgot to say my motherboard is an asus z77-v lk.

 

[Sergeant_Sneaky]

The CPU may be a small bottleneck, and when I say small I mean tiny but the performance issues you are are experiencing are something else. Are the cards hotter now there's two of them? They may be thermal throttling.
Also have you installed the latest graphics driver using DDU to uninstall your current ones?

 

[xxjonsyxx]

Not any hotter (70C hottest) the 3xwindforce cooler works pretty good, I also have 4x200mm, 2x120mm and a noctua D14 so everything pretty cool inside. I know the cpu might bottleneck at the very top end in CPU intensive games such as Planetside 2 but not like this. Used DDU to uninstall and install 14.2 (working drivers) then did it again and tried with 15.4 (beta drivers). I have three different Crossfire cables tried all three in every configuration (using one or two at a time).

 

[xxjonsyxx]

Ok, So I just finished using afterburner (rivatuner) and while playing Dying Light my GPUs are only going up to 36% usage and my CPU is at 95-100% usage. How the hell is that even possible? Maybe my CPU is trying to process part of the games physics or something, there should be no way a 3570k at 4.5ghz should be bottlenecking that hard. Either that or something else is holding my GPUs back from going all out.

 

[xxjonsyxx]

I did some more testing. I overclocked my CPU a little bit higher and it increased the fps and made my GPU usage go up to around 40% so everything points towards CPU bottlenecking. The weird part is this. When looking at the exact same spot in Dying Light (staring at a car on fire) I get with one GPU

41 FPS
70-80% CPU Usage
90-95% GPU Usage

When crossfiring staring at exact same spot I get

28 FPS
90-100% CPU Usage
40% GPU Usage on both cards

It shouldn't take 20% of my CPU power to crossfire and 40+40 does not equal the 90-100% GPU usage with one card. I am out of ideas any help would be appreciated.

 

[Sergeant_Sneaky]

Try resetting your CPU clock speeds to stock, it may sound silly but sometimes that could be the issue.
Are your CPU/GPU actually running at the speeds they're meant to be?

 

[xxjonsyxx]

I tried putting my CPU back to stock before I increased it to 4.6ghz (I wanted to see the fps difference from stock), GPU's running at 1100/1500 which is the stock overclock they get shipped with. Its weird as if crossfire is using 30% of my CPU power and I'm new to crossfire but I'm sure it isn't suppose to do that. As I said in my earlier reply with 1 GPU my CPU isn't bottlenecking at 40FPS but then with two cards its bottlenecking at 30FPS so some part of the crossfire process is stealing CPU power would be my best guess.