The onboard video probably sits on your AGP, so that won't work as AGP, by definition, only supports one card at a time (there is no AGP bridge). The PCI card that you use for your secondary monitor must specifically support that feature. I have a Matrox Millenium II that works wonderfully. I've tried a number of other cards that I have just lying around and they do not work. THey fight for dominance (or something like that
) and won't function.
So your 9800 only has one video out on it? That's too bad. ATI cards tend to do a super job with multiple monitors. I miss my 9500Pro