I've long been considering a dualboot with Win98SE on my main desktop that runs Win7-64. I'm confident I can find a netcard driver (there's even a packet driver... network cards have awesome support) and for sound I can always toss in an older PCI card (same for network, if I couldn't get it working).

For RAM I could buy rloew's patch, or limit it using .ini fixes.

The concern here is my graphics card. It's a Radeon HD 4870. The highest supported I've seen around is X800 series. I know that there are unofficial drivers for nVidia that support modern cards in their line, but what about ATI?

I also know there's VESA drivers and such, but these are unlikely to get me native resolution (1920x1200) and the performance necessary to run games on the system.

So I ask, does anybody know how to get a fairly modern Radeon working under 98SE? Has anybody done it?

AFAIK there is no such driver. I was also looking for for it for a couple of days, then gave up. (I had an ATI 1950 Pro and was thinking about an upgrade to HD3850 Pro, the fastest AGP card from ATI) It is the same situation for modern PCIE ATI cards like your 4870. You cannot get any of them work under Win9x.