Display problem with low level clouds

My FSX runs OK, about 20-25 FPS.Intel Pentium D 840 3.2 Ghz Dual CoreNVidia GeForce 6800 256 MB Video Ram2GB DDR2 RAMWindows XP with SP2Latest DriversAll is well except for if you look at the attached picture you will see the lower cloud layer is right up against the mountains and as I fly along the border where the clouds meet the mountains they are very "twitchy" (for lack of a better word). I have tried maxing weather settings to lowering them to minimal and the same problem still occurs. I have not yet installed ActiveSky into FSX yet, but I was wondering if that might cure the problem or is it a driver problem? Any help is greatly appreciated. Thanks,Darren http://forums.avsim.net/user_files/159790.jpg