During the P.O.S.T. if you write down the bios id # you could look it up on the web, and find the manufacturer, or you could look for a FCC id # on the board...but I would guess that the board is nothing special,as the OEMs tend to use as cheap components as possible, like onboard video, sound, modem,etc. I could be wrong and they're using a Micron..but I still hold to that probably being a "PC Chips" or other lesser known brand.
I also was surprised to find that a Gateway 500mhz system had a form of "softmenu" where I was able to bump the speed of the board,so you might get lucky and see some improvement without a mobo change