I have to do this when I run sa with skins,set the resolution to 1600x1200,set anti aliasing to 3,effects to high and enb series on...when I set fraps to 25 it just records with 17-25 and is full of laggs...this is the best method to edit sa videos imo..
With 15 fps,10 fps or 5 fps...just brilliant trick and smooth vids