audiohead - no problems for me in 9.0.20 with multi monitors, but I’m W10 and GeForce GT610s.
It’s interesting to read of some folks with CPU spiking. I am getting this in 9.0.2. I’m not sure if it actually started in 9.0.1. From reading around here, I guess I have to try disabling Hyperthreading as a first step, but it’s annoying that it wasn’t an issue in earlier versions of Cubase. I have 12 cores with hyperthreading on, so I shouldn’t be affected by this new multicore issue (as I understand it).