I guess I have this problem for a while now and tried many different approaches to fix it. So the problem is:

I have 8400GS and monitor connected via VGA port (not DVI, as I have no DVI monitor at this time). Problem is that once a while OSX (IPC-10.5.6) show me blue screen instead of login screen at startup and fullscreen game are turning videocard off too. I think problem is that it tries to take DVI port instead of VGA or something. Also same problem if I try to change resolution - I have to change it few time blindly for it to show me desktop instead of plain blue screen. I'm using nvinject at the moment, but I had same problem with EFI strings too. Had anyone meet same problem with it? Is there any solution, for example to tell via EFI string to use only VGA port and nothing else?

P.S.
QE/CI works fine with both NVInject and EFI strings though... if I playing, say. WOW in windowed mode it work quite fast and I have no problems at all. But if I go into fullscreen by mistake monitor turns of like VBLANK.