I moved my desktop machine to windows 8 pro and am running StSim v 1.3.0 on it with no problems. As far as StSim goes, the upgrade to 32 gb of ram and windows 8 pro posed no problems at all. I have the OS and software installed on an Intel solid state hard drive. StSim runs quickly and doesn’t hit the mechanical hard drive except to write results. This is a good set-up for StSim.