From what I can see, NWN 2 uses pretty much the same engine as Kotor 2, and Kotor 2 ran fine on my old machine. My new computer is faster in pretty much every department, but for some reason NWN 2 runs like crap. I haven't played a game this choppy since the PC port of Halo, but at least Bungie had an excuse: they didn't make a bad PC game, only a terrible PC port of an Xbox game.
I can't afford to upgrade my computer now, but why should I have to? For the life of me, I can't figure out why I (and some others from what I'm hearing) can't run this game at any respectable quality on machines that should be able to run it smoothly