http://www.hecticgeek.com/2016/11/ubuntu-16-10-flavors-comparison/ schreibt:
"Unlike Ubuntu and Ubuntu GNOME, Kubuntu 16.10 uses the 'CFQ' I/O scheduler
(this is the utility that controls read and write requests to the main storage device)
and under it the responsiveness was horrible!
Twice the system completely got stuck for about 3-4 seconds and most 'heavyweight' applications were only opened after the file copy finished.
There was also a big delay for VLC to open the multimedia file too.
However, then I changed the I/O scheduler to 'deadline' (the kernel comes with three actually), the one that's used by Ubuntu and Ubuntu GNOME by default, rebooted the computer and ran the test again.
And after the switch the responsiveness was so impressive that I would say that it was even slightly better than what I observed in Ubuntu and Ubuntu GNOME!"