CPU overload message while recording

So the support page is absolutely horrible. My cubase artist 8.5 is registered and activated and I couldn’t put a support ticket in for this because there were no registered products to choose from the mandatory list in order to start a ticket which is insane. With that out of the way, why am I getting this CPU overload message constantly while I try to record a guitar track. I have 8 drum tracks done and I’m trying to record a guytrack and the message keeps inturupting me. I’m using an iMac with sufficient ram. Please help

And since I can’t start a ticket because my 8.5 registration isn’t showing up as an option to select even though it’s registered I post a problem on here and nobody from Steinberg can reply?