The SBC6120 is fully static; you can reduce the clock speed to anything you're comfortable with :-) On a more serious note along these lines - the HD6120 datasheet gives a maximum clock of 5.1MHz, however DEC ran the DECmate (-II/PC278, that is; I don't know about the -I/VT278) at 8MHz. I used to ship 5MHz crystals with the full kits just to be on the safe side, but I've always run mine at 8MHz and I know many other people who have done the same. Never found one that's failed to work at this speed. Does anybody know if DEC was using specially selected 6120s, or is the datasheet just conservative? Bob