A small outline dual inline memory module (SODIMM) consists of a number of memory components (usually black) that are attached to a printed circuit board (usually green). SODIMMs get their name because they are smaller and thinner than regular DIMMs. The gold pins on the bottom of the SODIMM provide a connection between the module and a socket on a larger printed circuit board. The pins on the front and back of a SODIMM are not connected.
200-pin SODIMMs are used to provide DDR and DDR2 SDRAM memory for notebook computers. 200-pin SODIMMs are available in PC2700 DDR SDRAM, PC3200 DDR SDRAM, DDR2 PC2-6400 SDRAM, DDR2 PC2-5300 SDRAM, DDR2 PC2-4200 SDRAM and DDR2 PC2-3200 SDRAM. To use DDR or DDR2 memory, your system motherboard must have 200-pin SODIMM slots and a DDR- or DDR2-enabled chipset. A DDR or DDR2 SODIMM will not fit into a standard SDRAM SODIMM socket. (Information about which memory technology your system uses is included in the Crucial Memory Advisor tool.)
The number of black components on a 200-pin SODIMM can vary, but it always has 100 pins on the front and 100 pins on the back, for a total of 200. 200-pin SODIMMs are approximately 2.625 inches long and 1.25 inches high, though the heights can vary. Like 144-pin SODIMMs, 200-pin SODIMMs have one small notch within the row of pins; however, the notch on the 200-pin SODIMMs is closer to the left side of the module.