Why does Windows 7 Pro guest OS slow down in VirtualBox?

Question

virtual box

System: MacBook Pro running Catalina 10.15.7
Retina display 16" 3072 x 1920
Intel i9-9880H CPU @ 2.30GHz
16Gb DDR4 RAM
AMD Radeon Pro 5500M 4 GB
Intel UHD Graphics 630 1536 MB
Running in VirtualBox (version 6.1.14) guest Windows 7 Pro x64
in the guest OS, all Windows updates are installed, as well as add-ons from VB
. Under Windows, a fixed 100GB vhd is allocated, about 5GB of RAM and 4 threads, the rest of the settings are under the spoiler

spoiler

All mouse actions occur with large delays and jerks. The system hangs at the most minimal loads.
log file.

UPD.
I thought that it could be related to screen scaling
Even with the default scale of 100%, it still slows down, the browser is trite one tab with YouTube and that’s it, the OS freezes, the cursor disappears and the OS stops executing mouse commands
All to no avail, I can’t understand what the problem is.

UPD.2
I tried to install Windows 10 x64, but alas, everything is the same as with win7.
I do not know what to do.

Answer 1

In general, of course, first of all, you need to look at the logs. Perhaps there are some errors at the Virtualbox level. You can also look at the windows 7 event logs. Without this information, one can only speculate.
If my memory serves me, then windows needs special drivers to work in paravirtualization mode. When they are installed and the virtualization mode is switched, windows 7 itself will not understand that something needs to be changed in the drivers. Perhaps 10 learned this, but did not check. 7 certainly doesn't. So when changing the virtualization mode, you need to change drivers or reroll guest utilities. Or, in general, it is inside the guest windows 7 that is installed once during installation, only reinstalling or resetting statuses in the registry. (the search "Moving to new hardware windows 7" will help here).
You can also check if virtualization support is enabled. Could this be the problem?