[dba-Tech] 64-bit chips

I would guess that one cannot upgrade a 32-bit motherboard with a 64-bit
chip. This would imply that I demote my existing 32-bit boxes to
mail-server, ftp-server and such, and replace them on the development stage
with authentic ground-up 64-bit boxes. Is this correct, or is there any
point in attempting to salvage and re-use old hardware....
TIA,
Arthur