Ronin2, other than the RAM I have exactly the same system as you, and the same problem caused by swkotor2.exe taking 100% CPU (hence horrible performance/stuttering).
The only solution I have found to this is to revert to a non series 80 graphics driver. In my case I tried 77.77 and KOTOR2 ran fine, but both 81.85 and 81.87 caused huge slowdown (almost software rendering speed!)
Nvidia claimed that these series 80 drivers gave performance increases to dual core users, but in this case it does not seem to agree with this game. I assume that they have threaded the drivers and this game is calling the drivers in such a way that the threads are competing with each other rather than working concurrently.
Hope that helps.
