It's possible (even likey) that your motherboard doesn't support DIMMs >128MB in size. So when you add that large a DIMM to the board, it's essentially acting as a space-filler, and your RAM will be confined to the SIMMs. Ot might even mess up the MB's ability to assess the RAM. I'd see whether two large SIMMs and the 64MB DIMM add together
Clock speed of the RAM is also a possibility, though especially in cases where the MB wants PC100 RAM, if you use PC133, it mostly slows down appropriately.
If some of the other boxen have more recent (modern) MBs, especially if they have no SIMM slots, they're more likely to accept the 256MB chip.
(no subject)
Clock speed of the RAM is also a possibility, though especially in cases where the MB wants PC100 RAM, if you use PC133, it mostly slows down appropriately.
If some of the other boxen have more recent (modern) MBs, especially if they have no SIMM slots, they're more likely to accept the 256MB chip.
Good luck!