Stuttering Fix:
Different texture memory allotments, lower graphics settings and enabling/disabling vsync+triple buffering did not fix stutter on PC. Setup was: i7-2670QM 2.2GHz 8GB RAM, GTX 560M 2GB VRAM with game version 2.00.004, no background programs, latest drivers, proper defrag, etc. So, I dropped the maximum pre-rendered frames in the nvidia control panel to 1, and the stuttering is surprisingly gone. Hope this is helpful.

http://www.gog.com/en/forum/the_witcher_2/weird_stuttering_even_with_lowest_graphic_settings

setting the maximum pre-rendered frames in the nvidia control panel to 1 helped, but not as good as i hoped. the fix in the link works perfectly