hey mates. just am stopping by because i have the same problems. especially when it comes to the sliders.
strange part is, the sliders in the smart material editor work like a charm, but the ones on the layer settings are so laggy, they jump in ~30% intervals, what makes little tweaks pretty impossible.
i am working on 2k res, object is the robot template that ships along with 3d coat.
i7 6400k
32gb ram
gtx 1080
it feels really awkward. besides that, love it so far. Am still in the testing phase and just came from substance painter which i like too, but it is not as tailored to my painting needs as 3D coat is.