I can play the game on high objects dynamic lighting and avg 47fps (fraps). Although I have found two areas where everything becomes 5-6fps, but only if I walk in a certain direction. The strange thing is the menu, pda, and inventory lag as well. OS XPsp3, Athlon x2 @ 2.4ghz, 2gb DDR2 PC6400, ATI HD 3850 @710/999mhz. I really don't think it's my system, no other game does this. SOC, Oblivion, The Witcher. I am disabling all necessary user apps before I start the game as well.
Try adding 2 more Gigs of RAM for a start. This should help the FPS but won't make it blazing fast. Like I said, good for starters.
i think the game lags because i don't dump out the used memory? check the memory usage during the game, seems the longer you play the more memory keeps getting used up till you can't even play at 35 fps
Sounds like a memory leak, i think someone has the same problem over in another thread but personally i havent noticed any for me.