I have one of those old 2000 compatibles, and when I installed it, Windows had already assigned IRQ 11. (For something interesting related to the PCI bus.) I put it on IRQ 10 instead, and the network works fine. Windows does not indicate any conflicts, but when Windows starts up the music hangs up for a couple of seconds, so I am wondering if I should force the reallocation of the IRQs.
To clarify a bit, I am still letting W'98se start up with the introductory dialog box that lets you use tours on the CD to learn about the OS. It has its own special music that plays for about a minute. Since I don't really know much about how the PCI/IRQ business works, I am guessing that Windows does some probing around at startup and maybe when it tickles the network card it causes the sound card to hiccup or something like that. It remains to be seen if there will be any problems at other times.
Is this a problem that should be ignored? Or should I reserve IRQ 11 for the ISA card using the BIOS?