GTX 680 SLI causes black screen when alt + tab

Hello XS

I have asked in several forums and not yet found a solution to my problem so I thought I would give u guys a try. The problem I have is that when I alt + tab in a game(any game) sometimes my right screen(connected to my second card with 5 meter dvi cable) goes into power saving mode when that happens the rest of the screens blacks out after a while and I can only see the mouse pointer but it lags insanly. The computer cannot recover from this and I have to force reboot it. When I only run one card I never have this problem. I can game for hours without problem but sometimes when I alt + tab this happens. Anyone has any ideas? I have been trying different drivers as well without any success. So it only happens win SLI and when I minimize to desktop or maximize the game again

//Aqua