I am on a Mac laptop (MacBook Pro (16-inch, 2019) i7 / 32GB RAM) running Win10 in VirtualBox. I have noticed a degradation in performance of the VM when the VirtualBox VM window is not the focused window on the Mac. To be clear, this happens when I switch to another desktop, not just when the screen times-out, etc.
The slowdown doesn't happen immediately; it seems to be a gradual thing. The longer the VM window is not the focused window, the slower the VM will run. Network calls will begin to fail in Windows. Keyboard and mouse events will miss or replay too many times. Switching back to the VM window will immediately boost it back to normal.
This is primarily annoying because I generally access the VM via RDP from another machine. So, I have to keep babying the mac, keeping the machine next to me, keeping the VM fullscreen, moving the mouse around periodically. As long as I do this, everything works fine.
I am guessing this is some sort of power-saving feature on the mac; although, it happens even when plugged in. The VM has 4GB RAM. Closing other processes on the mac does not help, so I don't believe the mac is running out of resources.
How do I get the mac to respect that the app is currently in-use, even though it doesn't think so, or how do I get it to run full blast at all times?