ubuntu/kubuntu is sloooooooow!

[metin]

I can't give specific numbers regarding performance (I did not make any 
benchmarking) but when you use a system it is immediately evident 
whether it is fast performing or not. For example, when you click the 
k-menu (kde) or gnome-menu it takes up to two seconds for the menu to 
come up in (k)ubuntu while it is instantaneous in archlinux or pardus. 
This is more or less valid in every desktop operation. I am using all 
linuxes on the same machine so my system's specs are not relevant. In 
case you are curious, I will give the specs anyways:

processor: amd athlon-xp 2500
ram: ddr-1024mb
video card: nvidia 6800xt with nvidia proprietary drivers installed and 
working
hard disk capacity: 160gb

Note:
1- I have not tried xubuntu recently. My earlier experience it may be 
faster than kde/gnome but it is not a consideration here.
2- Ubuntu is faster in a faster machine, of course. But the above 
mentioned distros are even faster than ubuntu on the same machine.
3- My considerations are valid in at least four different machines on 
which I installed and used pardus, archlinux, debian, (k)ubuntu (the 
order is fastest to slowest in my experience)

Thank you for responses