Newbie: Ubuntu 20 and Mint 19 Running slowly on Catalina

[tenjin]

I've just installed the latest VirtualBox on Mac OSX 10.15.4

I have some experience running VMs with VMWare, but not VirtualBox, and while I am a dev on Mac and iOS I don't have much experience with Linux.

So, I've installed Linux Mint 19 and Ubuntu 20 on VirtualBox, and both run very slowly. Window refresh, mouse clicks, all very slow, and it keeps freezing. Same behaviour on both guest OSes.

I have tried to install the "guest additions" into both, and while no errors were displayed it doesn't feel like it is running any differently after installation.

Is there a way to check if the Guest Additions are installed and working as expected?

Can anyone suggest any fixes or investigations?

Thanks

Darren.

[tenjin]

In case anyone else is having similar problems, I think I have an answer.

Assuming you have:

- Turned on 3D Acceleration
- Installed Guest Additions
- Increased virtual cores to the number of actual cores on your Mac

Performance will still be poor on a Retina display, but if you have a second (non-Retina) display move the VirtualBox window to it and after a few seconds the speed will pick up significantly.

My installation is working fine on my second monitor.

HTH

Darren.