Identifying Memory Sticks

The following are a few memory types, starting with the earliest.

SDRAM SIMMs (around 1998?)
Had to be installed in matched pairs.


















SDRAM DIMMs (99-2002 ish)
Didn't need to be in matched pairs. You only needed to make sure you installed a stick of a speed the same or higher than that the processor on the motherboard required (PC66, PC100 or PC133).













RDRAM RIMMs (2002?)
Came in high end Pentium 4 machines, but didn't take off










DDR DIMMs (2002 onwards)
Labeled with either a PCxxxx or a DDRxxx number. The PC number is 8 x the DDR number.







DDR2 SDRAM













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A good place to check which memory you need, if you aren't sure, is
http://www.crucial.com/uk/