No, KDE is for people that like it.
Uneek has dual opteron (or at least single opteron) servers if I recall. I'd hardly call that a poor p3.
But overall, I find KDE buggy as hell. Maybe that was just in the environment it was in (very possible on that machine and I even had a drive die on me later down the road), but... there are certainly more sane X managers for me (and obviously Uneek). But then again, I find X is also an issue overall. Just depends on user I'd say (not skill but preference). I like Gentoo but some people can't stand it. Others like RedHat and I can't stand it...