I've been able to nurse my old (Sproggy's edition) XFCE installation to the current revision (with forum help ) on my laptop with dual 1.8Ghz cpu's & 1GB of ram and I'm happy with it.
I also run it on an old 1ghz AMD machine with 768MB of ram & it runs fine there too.
Consider writing this up as an article for PCLinuxOS Magazine, man. Good tech info is always welcome there, and may just spur other to try this excellent DE. I really should have mentioned it in my list earlier (hey, I was getting ready for bed...)