I am having this same issue I have a PCI-E All-In-Wonder 2006, which is powered by Radeon X1300, and then I have a PCI Radeon X1300. I don't have multiple PCI-E slots. For a brief moment I had 3 Monitors working, but it locked up and on reboot, I had an infinite loop error and could not boot normally unless I remove the card.
I purposely went out and bought what I thought would be compatible card, but I think it is an issue with mixing PCI with PCI-E, any confirmation on this? I'm running Vista 32 Bit.
If this won't work I did happen to buy 3 of these regular PCI X1300 cards which each support dual monitors, and I can free up a PCI slot if I get a USB wireless adapter as I currently have PCI wireless adapter taking up my last slot....should running 2 X1300 PCI dual monitor cards work?
I don't mean to hijack this thread but just to attract more attention to the issue of mixing PCI and PCI-E video, since this question never received a response, and not finding anything else on the goog