> > The issue is probably the signaling voltage and clock rate capability. well, I have just checked again, the Italian Wikipedia and the English Wikipedia do not report the same things about the PCI_X X___X in short, the Italian Wikipedia says PCI64 = PCI_X, just PCI64 is clocked slower while the English Wikipedia says PCI64 != PCI_X, but it doesn't explain why And the https://www.openpa.net/bus.html#pci doc is even more confusing in the table about the PCI buses used in PA-RISC computers overview: why things are named differently?!? What makes me perplex is: the PCI-X is physically a 3.3 V PCI slot with/out a voltage level shifter. So levels should be compatible, but so what is the difference between 64-bit PCI slot and PCI-X slot? In my head, there shouldn't be any significant physical differences between the slots. The newer PCI cards - 3.3V will fit and work in a PCI-X slot, and PCI-X cards will fit in an older PCI slot as long as the voltage - 3.3V - matches, and they should do! Now, I am even more perplex: need to check the PCI-64 and PCI-X specs, and compare them.
