Um, generally when one is working on a new framework one gets the
framework working, *then* optimizes it.
It is not beyond the bounds of possibility that KDE will speed up in
subsequent releases. (Some incredibly slothful things in KDE3 seem to be
fixed: I was forced into switching by Konsole's appallingly slow scrolling
under load in 3.5.x: you could see a wave of repainting creeping down the
screen at about five lines per second, on an Athlon IV with a load of only
2.5 or so...)