Help: gnome-shell(mutter) on ATI

[tornadory <tornadory gmail com>]

Hi, 

 I installed gnome-shell following
http://live.gnome.org/GnomeShell#Getting_Involved and it is exactly
worked, but it is too slow to do any other things after I
run ./gnome-shell --replace.

 I use Fedora 12 in an AMD+ATI(HD4500 series) mechine, and I found that
the Xorg will take up over 70% CPU load. But I could run compiz
normally.

 I thought that there must be something should be finished by Display
Hardware but did by CPU, but I do not know why. 

 Dose mutter need some special X/OpenGL requirement that compiz? I want
to know that which is must needed by mutter and which could cause the
situation I met?

Thanks in advance.