I have struggled through this for a few days now, tweaking settings etc but to no avail, it's time to ask for help !I have a BFG GeForce 6600GT OC on my home PC running FS9.1 and whenever I set anti aliasing to 8xS (the max it will allow) I eventually get my system to either crash completely or go into a re-boot.It happens at different points, sometimes during taxi, during take off roll, cruise or on approach, happens every time, no matter what aircraft, airport or region of the World.I have tried changing as many display options as I can think of but the result is always the same.Another anomoly at 8xS is the aircraft does not appear in the FS menu window.Whenever I lower the AA settings it all runs flawlessly and the aircraft appears again in the window.I was using the latest NVIDIA drivers (81.98 I think - the ones released on 21 Dec 2005) and I tried going back and using the 78.01 drivers but this did not solve the problem either.I've run out of ideas, does anyone have any suggestions?System specsIntel P4 3.0GHz HT2 GB PC4200 DDR2 SDRAMBFG GeFroce 6600GT OCSoundblaster Audigy 2ZSWin XP Media Center SP2FS9.1 (patched)Edit:Forgot to say also I have flashing textures occassionally, but always at night, whenever I turn the lights on. The whole outer textures begin to flash like crazy, also happens to AI planes when they turn their lights on. Lots of flashing in water too and sometimes in clouds, this happens at 8xS or at 4 anti aliasing. If anyone can help with this too that would be great !Also, not sure whether it is related or not, but sometimes when using IE or notepad I get strange lines across the screen, starting on the right hand edge of the screen, if I select all text then the lines disappear. It does not happen often but its annoying when it does. I have tried my monitor on another PC and it has not had this lines problem yet after 3 days, so I'm not sure it is the monitor now?????Thanks for any helpGarry

Overheating. More AA = more overheating.Allcott

Perfect, you got it.I moved one of my PCI cards to another slot which gave the fan more space and the idle temp went from 77 to 52.I ran FS and it went like a dream 8xS AA, no crashes, and if I don't use Full screen mode I even get the aircraft back in the select aircraft scren window.Thanks Allcott, if it had not been for you I would not have realised that my card was running too hot, you solved my problem !Thanks a lotGarry