I had a similar problem and traced it to my video card overheating. I downloaded this tool from the below link and discovered my card was running in the red zone at 76 degrees C or higher. http://downloads.guru3d.com/Guru3D---NvTem...nload-1194.htmlNote: I believe tool only works for Nvidia chipsetsI put a 3rd party fan on it which helped drive the temperature down, but it appeared to be damaged (confirmed this damage can be permanent after reading several web links about this topic)After replaceing the card, my problem went away and my video card now runs in thelow 60's (low yellow band) and I haven't seen this problem since.Bingo

My card has a custom cooler and runs in the 40s to 50s, so overheating can't be the problem.I really think it's SP2, since SP1 runs a-ok. At least I didn't spot a single glitch on a one hour flight yesterday...

Geez, I almost had it.Installed SP2 over a SP1 installation, deleted the "Shaders" folder in "Documents And Settings\[username]\Local Settings\Application Data\Microsoft\FSX", went on a simple test flight in the CRJ. No errors for 30 minutes. Wanted to be sure. Rebooted and set up KBOS - KDCA. Eventless flight till final. Intercepted the localizer for RWY 1 and - bam - autogen spikes and display corruption all around. ARRRRRRGH! *Pulls out hair*

Well, I'm done with the 4850, traded it in for a 9800GTX+ 512 (from a non-simmer). Apart from the graphics corruption problem, performance with the ATI card went down to crawl and stutter once I've encountered overcast conditions. Even my 8800GTS 640 can handle those situations without a twitch.Bottom line: FSX doesn't like ATI, unless you bring a 4870X2.