The performance is fine 99% of the time it's just those stutters....
btw: I've been playing with WSE2 turned on today after since it's been released more or less just to see if it's an alternative to my regular cRPG and because of this thread. Well I'm not gonna use it again any time near soon because my dx9 cRPG is the same exact thing but without those stutters which are NOT lags.
So yeah, technically it's 'unplayable'.