It must be technical/bug sort of problem, then. The 311 is easily powerful enough to run the game smoothly. Maybe it just doesn't work well with the Atom/Ion/chipset or something. I have rarely run into the usual compatibility issues that plague notebooks with the 311, probably because it's Nvidia and not Intel, but I guess there are bound to be a few :/

Let me guess...Windows 7? if you'll do a search of this forum there are several tweaks you can try for Win 7 but in the end this game is just buggy on win 7. Even on my hexacore with an HD4850 it will sometimes chug but I did manage to get it playable by changing my native res from 1600 to 1280 but strangely enough I didn't really have to do anything on my E350 netbook, for whatever reason it seems to like my E350 a little better than the hexacore.

But if you are on win 7 there are several tweaks to try, from forcing AA to setting affinty. In my case the combo of affinty and lowering my res to 1280 (otherwise the far left inventory is off screen) made it playable although there are sections that will still drop to 25FPS causing a little chugging.