Go into your Cubase, studio, studio setup, and activate Asio-guard. Try out the different settings (low, normal, high), and look at your VST performance panel the same time, see if the realtime bar is lowered. It is here on my setup on windows 10.
Also try out Steinbergs power scheme, in the same panel as above. This will disable some cpu power saving features, which will make Cubase run more smooth without any hiccups.
I guess you have access to the exact same features on your Mac computer.
SLL