It seems that the performance problems were being caused by a conflict with xFire.  Adding a simple line to the xfire_game.ini file in your xfire directory will solve the problems.  NWN2 is as smooth as silk now, so I take back some of the mean things I said in a previous post about performance issues.

If you need a copy of my .ini file to make NWN2 run correctly, email me (above link).