I've been having major frame-drop problems with my 2xHD5850 CF in Battlefield 3. Settings high 1920x1080p and 2xMSSA with average fps 45-65 but periodic fast frame-drops to 1fps or sometimes 15-25fps for a second or 1,5. I was running exact same clocks on both cards but now I have the primary card running 840/1175 core/mem and the secondary card 850/1200. And the problem seems to be away. No more red low fps numbers with "render.drawfps 1" in the console. You can achieve this by using overdrive option in CCC. Disable synchronise gpu's in Afterburner if you use it. The core/mem values are just the maximum overclock that my different brand cards can handle on stock voltage. I switched the slower one to primary because of heat issues. Maybe there is some sort of bottleneck when cards are clocked exactly the same. Or benefit if your primary card is a notch slower than the second card so it doesn't have to wait for data or something when doing most of the work. What ever, as long as it works. I haven't been testing for long so I'll update my post after a long session of bf3 later this week or so. update, Mar 15, 2012 I've been playing bf3 for a few hours. Turned HT on my i7 back on, V-sync on, tripple buffer and my frame-drop problem seems to be gone for the most part exept when spawning. I'll update again later on. update, Mar 17, 2012 Framedrop problem is gone. Also when spawning.