Created attachment 852862 [details]
Screenshot with top while packagekit is running

Trying to run "yast online_update" after boot, I had to wait a rather long time
until package kit did no longer block yast.
While waiting I was running top to see that pckagekit downloads updates one by
one (as it seems) and runs applydeltarpm (which is a CPU hog).
For a fast net, the time applydeltarpm consumes is much longer than the
download times. Considering I have 8 threads, available using multiple
appldeltarpm in parallel might reduce the overall waiting time.
I'm aware that the applydeltrpm may also use a lot of RAM, depending on the
details.