Skyrim and Valve games don't use crossfire, can I force it?

[NibblyPig]

I have a 2 x 280X in crossfire. Using the afterburner program when playing Skyrim and Left4dead 2, I can see that only one of the GPUs is being used.

I thought perhaps that something was wrong, but I tried the original Bioshock and the crossfire logo appeared and both cards were showing as being used in afterburner.

I've tried everything I can think of to get crossfire working with skyrim but it simply refuses to use my other graphics card. I have tried the latest drivers and also the beta drivers, fiddling with profiles, and using a program I downloaded to 'force' crossfire, but nothing has worked.

Any ideas on how I can get skyrim or left4dead 2 (and presumably other valve games) to use both cards?

 

[Pinhedd]

Skyrim has had notorious Crossfire issues since it came out. The game logic, physics, and the frame rate are all tightly coupled (which is really a big nono in game design) so this really comes as no surprise. I just turn it off for that game.

As for L4D2, I have no idea. I haven't played it. It may simply lack a Crossfire profile. You can forcibly enable it for all games, including those that do not have profiles.

 

[NibblyPig]

Can you explain how to force it? I have tried creating a profile manually for the .exe and have also enabled the 'enable crossfire for games without a profile' option but neither seem to activate it.

 

[Pinhedd]

Can you explain how to force it? I have tried creating a profile manually for the .exe and have also enabled the 'enable crossfire for games without a profile' option but neither seem to activate it.

If you have checked the "enable crossfire for games without a profile" button and it still does not work then it will most likely not work at all.

 

[NibblyPig]

I've figured it out, crossfire doesn't work unless you use fullscreen. If only they'd mentioned that somewhere in the manual, or in the control panel. Set it to fullscreen and boom instantly frame rate doubled.