Cant do anything else anymore while I bounce track in Cubase

Hi, I am running Cubase 9.5 on a Mac Pro, Late 2013, 3.7 GHz Quad-Core Intel Xeon E5, 32 GB Memory

Since I moved up to Cubase 9 and High Sierra (did this simultaneously) I can not do anything anymore during a Cubase bounce. It feels like being back in 2003. The Computer kind of freezes for 10 seconds, then it lets me open up a folder or sth like that before it freezes again. When the bounce is over,
everything is back to normal. What also doesn’t work at all is to listen to a mp3 or wav track in Finder while Cubase bounces a track. For the last 10 years
that has never been an issue. Now it awfully distorts the signal I want to listen to. Again, after the bounce is over, all back to normal. I was wondering if it has to do with RAM, but I tried it and quit all other programs and then only bounced a small track in cubase, still the same story.

Anyone has the same issue? Thanks!

It all depends on what you are bouncing? Using external instruments or many cpu intensive plugins? Your Mac is 5 years old! So not the most current to say the least? Anyway, some more information on ‘what’ you’re trying to bounce would help? Even the latest models with 10+ cores can have real time audio processing issues? Could be configuration, could be a driver, could be anything.