As for the guest performance, I used 'sshd' option to connect
to netinst and
watch the CPU usage using `top` throughout installation.
* When the spinner is animated, Xorg consumes 50% CPU.
* If I close the VM window, it drops to 40%.
* If I open the window again, but switch the VM to TTY2 (text mode), it drops
to 25%.
* If I go back to TTY6 (graphical mode) and open the root password spoke,
which makes the spinner disappear temporarily, the usage goes to 0% (!).
* When I close the root password spoke and the spinner appears again, it
again consumes 50%.
* During certain periods of post-installation phase (especially to the end),
the Xorg usage climbs up to 90% and holds steady for a minute or two.
The changes are immediate and reproducible (at least here).
I reported this here:
https://bugzilla.redhat.com/show_bug.cgi?id=1204242