Why do systems in VirtualBox slow down?

Question

virtual box

Characteristics of a laptop under Windows 10:
-intel core i5
-8GB of RAM
-ssd
This is the problem: I installed
Linux mint, Elementary, Manjaro (xfce, kde). All systems slow down. Installed guest additions. I allocated 2GB of RAM for all systems, 15-25GB on disk, 64MB of video memory. In the task manager, Wirth. The machine percent is loaded at 100%, although in the settings the load limit is 100%. The virtual box itself eats 12% of the processor.
Virtualization technology seems to be enabled.
The checkboxes are on VT-x, Nested Paging.
Why is the processor Wirth. machines are loaded at 100% and how to solve it?

Answer 1

8 GB is not enough even for work, not to mention VB
2 GB is only good for a console server, but not for graphics - of course it will slow down

Answer 2

Allocate more CPU in settings I think.