IrnBruu: I had a problem with nwn when I got a new graphics card, it ran horrendously (10 fps max kind of bad). Turned out to be newer versions of the open gl driver were bad with older games...
NWN1 uses OpenGL but NWN2 uses DirectX9.
Mitchnicol, could you please post details of your hardware? (in particular, CPU and graphics card). NWN2 was pretty demanding for its time (and still can be with maximum graphics goodness, transparency AA and improved texture mods). In particular, most laptops (with their limited graphics cards) are likely to struggle, but recent desktop graphics cards should be OK.