> Do you know if the R[34]k Indigos differ beyond a different CPU? > I believe the FP units may be different, the memory architecture is WAY different. R3K used proprietary 4MB and 8MB memory modules, whereas the R4K version used 72-pin SIMMS which I believe were FPM. The graphics cards work interchangeably between the two, at least all the incarnations that I have tried. -Steve