If the memory is working right, it will show up regardless of the OS you are running.
I don't know much about the PPC cards, but from what I understand some Phase5/DCE cards can be picky about memory types. I use a 64mb FPM simm in my 1260 and it works great.
Make sure the memory is the right type specified by
the manufacturer, i.e you may need to use FPM simms instead of EDO.
