Crossfire not working on some games

[Recoan0]

I recently bought Arma 3, and when I started it I noticed that my fps was pretty low. Starting up GPU-Z I noticed that my 2nd GPU wasn't being utilized while GPU-Z said crossfire is enabled.
I have been experiencing this problem with multiple games that should support Crossfire, like StarCitizen, Arma 3 and Metal Gear Solid: Ground Zeroes. Crossfire does however work in games like Battlefield 4, Sins of a Solar empire: Rebellion and Kerbal Space Program. So I am wondering whether this is something that is caused by my GPU-drivers (Using Cataclyst Omega 14.12 atm) or that this is a weird windows glitch.

Does anyone know how to solve this?

Thanks for taking a look,
Dustin

My system Specs:

i7 4770k
Asus Maximus VI Hero
2x R9 290 Tri-X
1100 watt Aerocool Strike-X EN53761
Windows 8.1 64-bit

Iiyama 28" 4K Ultra HD Monitor B2888UHSU

 

[airborn824]

In my experience you must be in full screen for xFire

 

[sla70r]

Not everything is optimized for SLI/crossfire. I have not been able to get Day-z to SLI even using tricks that helped others.

 

[maddogfargo]

If you just have 1 monitor you won't see GPUz on your desktop report that crossfire is being used. Crossfire only functions when you are in full-screen 3D. You need to tab out of full screen 3D to see your desktop and GPUz. When on the desktop, you are dropped down to 1 GPU. Windowed or Windowed full-screen you also go down to 1 GPU.

Use MSI Afterburner or your manufacturer's GPU monitoring tool that uses an on screen display. This will tell you if the 2nd GPU is being loaded up and used in-game.

 

[Recoan0]

In my experience you must be in full screen for xFire

I Am Running in full-screen.

 

[Recoan0]

If you just have 1 monitor you won't see GPUz on your desktop report that crossfire is being used. Crossfire only functions when you are in full-screen 3D. You need to tab out of full screen 3D to see your desktop and GPUz. When on the desktop, you are dropped down to 1 GPU. Windowed or Windowed full-screen you also go down to 1 GPU.

Use MSI Afterburner or your manufacturer's GPU monitoring tool that uses an on screen display. This will tell you if the 2nd GPU is being loaded up and used in-game.

You can see the history of your gpu-usage for the last 1 minute or so, i based my obeservations on that. i'll try MSI afterburner.

 

[Recoan0]

MSI Afterburner OSD says both graphics cards are fluctuating between 0 and 50%, but when i alt-tab and look at the graphs in msi-afterburner itself both are fluctuation between 0% and 100%. No idea why it's suddenly different, but it's still weird.