Just updated to Parallels Desktop for Mac 20.3.1, which I'm running on an iMac Pro intel machine in Monterey 12.7.4 My virtual machine is El Capitain. This works fine, if I boot El Capitain from OFF. But if I susped my session and come back to it in future, it's painfully slow. Each operation takes about 20-30 seconds, and I have to shut it down and restart El Capitain again for it to behave properly. I think this was mentioned as being FIXED in 20.3.1, but it seems to be a problem now for me.