same problem here with a Dell XPS 630i!
I tried a lot of different linux distributions ( Debian alike ) with live CD, without success!
If i remember correct even a freeBSD system "pc-bsd" hangs!
I think there is no difference in performance for a normal user using a 32/64bit OS, but i'm really interested in the reason for that issue!
So, keep on googling
found this advice at ubuntu bug report, i'll try that tonight
Found a better work around which worked for me and other Dell owners.
Boot from CD or DVD
Highlight your preferred install option (I prefer compatibility mode)
Hit the tab key to add boot options
Add to end of existing string "mem=xxx" (without quotes and replace xxx with your memory
Hit return to start boot process
Formula to determine your memory is:
replace X with number of GB ram you have.
4GB Ram = 4*1024*1024*1024=4294967296
So for Dell 64 bit systems with 4GB ram, add "mem=4294967296" to the end of the boot options string.
For 6GB ram systems, add "mem=6442450944.
I've used for Ubuntu and Arch Linux and has worked both times, but without the string, my system appears to freeze but is actually performing a kernel panic.
P.S. Stumbled across this work around on the Fedora forums.
that's the solution, happy again