Thanks, I thought so, since with V-Sync and AA/Box there seems to be a little FPS drop compared to Edge Detect. Image quality 4x AA Edge Detect (effective to 12xAA) also seem better, although several ground objects (hangars, tents and some static planes) tend to flicker a bit.
Still, I'd go with the better performance and the better overall image quality of edge detect AA.
thank u sooooo much my problem solved I have a 4890 ,1024 I wasthinkingto change it cause of purple problem but now I like it again thanks for your good advice ,,,