Since the Galil card (DMC-1750 in my case) handles most of the work, it would seem that the PC processor speed would not be such a large factor using Mach3. I can see why speed is important when using the parallel port, but from what I understand Mach3 is just feeding a stream of 3D points for the DMC-1750 to use with linear interpolation.
My problem is that my Galil card uses the ISA bus and it is difficult (or expensive) to find a motherboard that will run at 1 GHz and that has an ISA port. I have located a used board in China for about $80 that should handle the 478 socket Celeron processor that I have from another PC. Right now I am running with the Galil Terminal program on an ancient Pentium 3 or 4 processor in Windows 98. I just purchased BobCad and would really like to upgrade to Mach3 for a more user friendly interface to my 3 axis Bridgeport mill. I have considered buying a PCI version such as DCM-1830 which might end up costing about the same as upgrading the motherboard.
Does anyone have experience with Mach3 (or Mach2) using a slower PC? I am not sure my old PC will even run with Windows 2000 or XP, but I think it might work. I probably will need to upgrade my video card in any case. Tech support agrees with my opening comment, but they cannot say that it will work with a slow PC since they cannot be certain and do not want warranty problems. I am open to other suggestions, but would prefer to spend my limited money on tooling if I do not really need the faster PC.
Bob Butcher