Inserting Nectar as a track effect does not work well. Effects stutter, and sometimes simply won't work. I've had to use it as a Bus effect only. It happily lives there.
I am win 7 with an i7 and 16 gig of ram. Not even close to pushing either the ram or the chip, so that's not the problem.
I also tried to insert neutron as a clip effect. That crashed CW as it loaded an endless loop of Neutron iterations. Fortunately I was just experimenting and didn't blow up anything critical