Thanks for your suggestion, Allcott.I really appreciate that people are still trying to give advice. It's the reason I'm posting here in the first place.I made your very same assumption a while ago, and started playing with visibility and cloud distance. Unfortunally, no matter what the visibility setting is, and assuming the skies are clear, the very last horizon line in the distance shakes and trembles. And if this last line is not straight (i.e. mountains), the shaking is horrible. It's as if the outline of distant mountains is continuosly changing, and it does more so if I shift my view point.I can't find another way to describe the problem.Than there is this awful rattling of the line where clouds intersect mountains, regardless of distance. The mixing of the two makes flying visually impossible to tolerate. I really can't figure out what's going on, and I tell you, I'm beginning not to give a damn any more. I'll go back to first person shooters and wait another two years. You just come to a point where you say "********** it all".thanks againluca

In that case you have the old `table fog` problem with your card - there were lots of posts on how to fix it. Sorry don't have the threads to and but if you search on table fog you'll find it.Dont give up!Allcott

Hello Luca,I'm flying a lot in Switzerland - Italy with meshes from Lago-Pignot, and I most say that the problem was greatly reduced setting the Settings > Display > Weather like the screenshot I include, andthe part - Terrain - of the FS9.cfg like this:[DISPLAY]UPPER_FRAMERATE_LIMIT=32TEXTURE_BANDWIDTH_MULT=380[TERRAIN]TERRAIN_ERROR_FACTOR=100.000000TERRAIN_MIN_DEM_AREA=10.000000TERRAIN_MAX_DEM_AREA=1000.000000TERRAIN_MAX_VERTEX_LEVEL=19TERRAIN_TEXTURE_SIZE_EXP=8TERRAIN_AUTOGEN_DENSITY=1TERRAIN_USE_GRADIENT_MAP=1TERRAIN_EXTENDED_TEXTURES=1TERRAIN_DEFAULT_RADIUS=10.000000TERRAIN_EXTENDED_RADIUS=20.000000TERRAIN_EXTENDED_LEVELS=1307992Give it a try!AC5