Hello,After more than a year experimenting different drivers/tweaks/settings combinations with FS9 running on a nvidia FX5900, the conclusion is that AA and clouds doesn't mix well.I'm running FS9 with AA set at 4xS (a little bit lower quality than 4x but more performant). I get around 25FPS with clear sky, AI traffic, very detailed sceneries and quality sliders nearly maxed.As soon as clouds fill the sky, the FPS can low to 8FPS very easy. If I point the view to a clear sky area then the FPS go up again.I've heard that the big problem with the nvidia FX cards is that they also apply antialias to the clouds, opposed to the radeon 9700 and 9800. I've tested a radeon 9800 card and the performance is not affected with clouds when antialias is enabled.I suppose the same problem is present on different nvidia FX cards.Does anyone knows if it's possible to overcome this ? is it possible to apply a tweak or something to tell the nvidia card to not AA the clouds on FS2004 ?My specs:Win XP PRO SP2, P4 2.8Ghz, 1GB RAM, Nvidia FX5900 128MB, FS9 (with patch), 1280x1024x32Thank you.

ATI cards don't have a 4xS mode and 4xS mode is better quality than 4x mode but slower. If you want to compare results with the ATI card then use 4x mode in the Nvidia card. Also lowering the res helps performance with clouds. I have a 6800 Ultra and it can get slow with 4x AA and 8x AF at 1600x1200 with many clouds but lowering the res to 1024x768 gives a big improvement in performance with many clouds and I'd rather use that res but it's not the native res on my LCD and would look awful. Also there are clouds that you can download that are smaller in size than the default ones and perform much better.

I also have a 5900 Ultra and I dont have the low fps issue, what clouds are you using?

I'm using Chris Willis Clouds. My 5900 is not ultra but I don't think there's a great difference.Are you running at 4x or 4xS AA ?

I'm thinking setting your card AA and AF at 2, and image setting to performance, turn off Vsync, make sure AA in FS is dissabled, lock your fps at 25 to start, set mips in game to 4, ingame lights to 5, set FS to bilinier. Also, play with your weather sliders, mine are set to;sight distance 110cloud draw 703d cloud percentage 80cloud coverage density highGo to guru3d.com and get newest driversNy ultra is a 256mb card if that makes the differance.