I has a Radeon 9800 pro 125mb graphic card and today I was looking at the different settings for it and the effects on FS2004. My question is what is difference between 4x and 6x? Cause I had my anti aliasing on 6x, then changed it to 4x to see what the diffence would be, but I didn't see any diffence in FS2004 at all.

I too don't notice the difference between 4/6 unless I really look. 6 looks a LOT softer. I keep it on 4 because the shapes are a little sharper.

Tomorrow Im going to fly with it on 4x, maybe if I look long enough I will notice something. The one thing I did notice that on 4x I picked up 2 or 3 framerates. (When I was changing the setting I was looking at the framerates too, but I never look at the framerates when I fly)Oh and I have a 128mb graphic card, not a 125 :-lol

This is normal! the Radeon series are known to have introduced antialising and Anisotropic filtering "for free" (that is with little difference as compared to without), all this, compared to the Nvidia cards (the ones avail at the release of the Radeon series) which are known to not perform the same with AA and AF on. I don't know about the latest Nvidia though.Enjoy AA and AF!