Strange behaviour running latest rawhide on Dell Optiplex 760

[Michael Wiktowy]

I have made a LiveUSB stick with Fedora 11 Beta and have updated it to
the latest rawhide updates. It boots just fine on most of the machines
that I have (Dell Precision 690 and Optiplex 755) but exhibits bizarre
behaviour with any Optiplex 760 that I try to boot on.

What happens is that it will start to boot but will hang part way into
the sequence. At this point, I can press (but not hold) the power
button and that seems to jog it such that it will boot a little bit
more. I can keep pressing the power button over and over (it takes
about 20 times or so) and it will prod the boot along such that it
will eventually boot to a fully functional desktop. If I don't press
the power button, it will hang indefinitely.

There are still issues with the desktop in that it is really laggy and
text does not scroll smoothly in the terminal and it seems to take
multiple keystrokes to do anything but there is no indication as to
what is causing the load or latency.  Top is clean (although won't
update unless I press a keystroke) and /var/log/messages doesn't have
anything really unusual in it.

The network card doesn't work either.

These are regressions from Fedora 10 which worked fine on this machine.

Any thoughts on where I should look to even start to file a bug report
that won't to so vague as to be completely ignored?

/Mike