Sully you really need to tweak a bunch of settings in your BIOS. Also, if you haven't already you should update to the UL BIOS as that will give you the option to change to 4 way interleaving. Basically go through your BIOS and change every memory setting you can to the one that gives higher performance (if you're RAM is high quality that is).
If noone offers u any help when i have a look tomorrow i'll set my bios up per for ur PC100 ram and see what i can squeeze out of it and post the settings.
Have u got the UL Bios?
Force 4-way interleaving in Soft Menu with this bios and an extra option called "4k page flip" (i think?) made big difference to my scores