Overclocking Asus P5B Deluxe versus abit IP35 Pro

I would appreciate a little help on understanding the difference between
these two boards. I have the abit IP35 Pro/E6750 system slightly over
clocked - all I did was increase the FSB to 400 and let her rip. I have not
had even a hint of a problem and the temps seem pretty low with the standard
Intel cooler. The Asus P5B Deluxe/E6600 system is running at the stock
settings with a Zalman 9700 cooler. Both systems have 2 Gig of corsair 800
DDR2 C4 memory running at 4-4-4-12 timings at 2.1 volts. Both systems have
a Raid0 configuration. I just updated the Asus board to the latest 12.26
BIOS version. The problem I am having is almost every time I make a change
to one of the P5B BIOS Advanced settings the system shuts down and reboots
(sometimes) and comes back with a message saying something to the effect
that the BIOS settings need to be changed. Sometimes the system just hangs
on the "auto reboot" and I have to turn the power off and back on again to
get it to boot to the BIOS. I have had this issue since day one when I had
to change the voltage and timings for the Corsair Memory. After the reboot
I go into the BIOS and change nothing and the system boots up and runs
normally with the new settings. Is this just the way ASUS P5B acts or is
something wrong. I was never really concerned about this strange behavior
until I got the abit IP35 Pro board and had zero "problems." The Asus
system is over a year old and has never crashed or blue screened so it is
very solid. I am just getting greedy and want it to run a little faster via
over clocking.