I have my i930 OC'd to approx. 3.8 GHZ, and all works well.
However, whenever I change my Video card, hard drives,.... she'll POST with warnings and appear to shutdown.
I give it a second, and then it'll switch itself on again, and she'll post with warnings. But I do get into bios , and it all works fine again.
To me, if it detects ANY hardware changes?, it sets itself momentarily to "defaults" until it stabilizes for a few seconds.
-and YES!!!, update your BIOS to the latest, I thinks its "F5" still.
As far as drivers, I've used the "newer" online Intel "Rapid Storage" Intel-RST drivers for the X58/ahci/ICH10R...chipsets.
I threw that "buggy" Gigabyte CD driver in the garbage awhile back.
In other words, for most situations regarding the rest of the devices, just download/install Gigabytes' "latest" drivers online.
-anyway, I'm just trying to explain similar symptoms as what I get.
...hope this may help.