KDE 4.2 beta

I am a GNOME user( I have been using linux(dual boot) for the last seven years, and I threw Windows XP three years ago and have been using GNOME since then ). I have a P4 1.7ghz with 256MB ram and a geforce2 graphics card. Few months back ,after reading a lot about KDE4 ,I gave it a try and I was disappointed. It was very slow compared to GNOME running on my system.

Now again there is lot of news regarding KDE 4.2 . I wanted to know whats the advantage of using KDE over GNOME. What are the main features in KDE 4.2 compared to GNOME 2.24 .

Can my computer run KDE 4.2 ?