trag said:

The 8100 was the first Mac with a Fast SCSI bus in addition to the regular slow bus.  While the Q900/950 had dual SCSI busses, they were both based on the 53c96.   The 8100 used the  53CF96 for it's internal Fast bus.

After the 8100, Apple switched to their "MESH" chip for the internal Fast SCSI busses in the PCI PowerMacs.  I suspect, but don't know, that MESH is really just a licensed 53CF96.   One of these days, maybe I'll try replacing one with the other to prove or disprove it.

Click to expand...

In discussing this with dad, is it possible to replace the 53C96 chip with the 53CF96 and automatically improve performance? Or does the ROM has something to say about the speed limits the buss can have? He has been wondering for months, what if he replaced the old slow 5380 from the old Macs with a faster chip like the 53C96. Pin to pin compatibility would be an issue but an adapter could fix that. But would ROM slow down the data transfers?

In the 8Bit days, dad has swapped out older 6502s from various machines with faster ones and managed to get some improvement out of the old machine.