Funky X11 on Summer 2000 iMac

[Michael A. Peters]

[mpeters at gourmet ~]$ cat /proc/cpuinfo 
processor       : 0
cpu             : 740/750
temperature     : 44 C (uncalibrated)
clock           : 450MHz
revision        : 131.0 (pvr 0008 8300)
bogomips        : 897.02
machine         : PowerMac2,2
motherboard     : PowerMac2,2 MacRISC2 MacRISC Power Macintosh
detected as     : 66 (iMac FireWire)
pmac flags      : 00000014
L2 cache        : 512K unified
memory          : 384MB
pmac-generation : NewWorld


Just installed todays rawhide.
iMac kept rebooting during rawhide install - at random places but always
while downloading, doing a minimal install got it to install all the
way.

Machine did not randomly reboot in OS 9.2

Then -

yum groupinstall "X Window System" "GNOME Desktop Environment" "GNOME
Software Development" went fine without a hitch.

I'm currently booting into run level 3 - X11 starts rather slowly (via
startx) and ssh'ing in and running top shows it using an insane amount
of the CPU - between 94 and 99.

It will eventually suddenly drop and I can move the mouse etc. but as
soon as I click something, anything, it gets bogged down again and the
usage of X in top skyrockets.

my xorg.conf and Xorg.0.log file can be viewed here:
http://mpeters.us/imac_xorg/

Anyone know what's going on?
I'm tempted to see if it works better via remote xdmcp - but not sure I
want to enable gdm if it eats the CPU whenever it does anything X
related.