Terrain mesh suttters

[sonic]

I was wondering before I download the rose burgers sorry no offense to him I want even try to spell his name. terrain mesh agian before everything ran smooth for the most part, but when I added the 70m mesh I had huge stutters is the a setting in the .cfg or something to deal with that I have applied all the major tweaks and right now everything is really smooth. But I want terrain mesh. I have a 8880 gt 512 and everthing set to max.