I'm currently having a problem where the 2nd GPU of my graphics card, the HD Radeon 6990, is not enabling. I did a clean install of drivers and am currently using the 15.7 suite, however, no matter what I seem to do, the 2nd GPU does not seem to be enabling! I tried bench marking it with Heaven Benchmark 4.0 , whilst monitoring with MSI Afterburner, and still nothing. I had this issue a while ago and the answer was simply that I had to be playing games in full-screen mode, sadly this doesn't seem to be the fix this time round. Any help would be greatly appreciated, thanks in advance!