240-pin DIMM Approx. 5.25 in. by 1.18 in. (133.35 mm by 30 mm) A dual inline memory module (DIMM) consists of a number of memory components (usually black) that are attached to a printed circuit board (usually green). The gold pins on the bottom of the DIMM provide a connection between the module & a socket on a larger printed circuit board. The pins on the front & back of a DIMM are not connected to each other. 240-pin DIMMs are used to provide DDR2 SDRAM memory for desktop computers. DDR2 is a leading-edge generation of memory with an enhanced architecture that allows it to transmit data very fast. Each 240-pin DIMM provides a 64-bit data path (72-bit for ECC or registered or Fully Buffered modules). (The Ballistix & Ballistix Tracer high-performance memory do not come in 72-bit or registered modules. Standard DDR2 240-pin DIMMs are available in DDR2 PC2-3200 SDRAM, DDR2 PC2-4200 SDRAM, DDR2 PC2-5300 SDRAM, & PC2-6400 SDRAM To use DDR2 memory, your system motherboard must have 240-pin DIMM slots & a DDR2-enabled chipset. A DDR2 SDRAM DIMM will not fit into a standard SDRAM DIMM socket or a DDR DIMM socket. The number of black components on a 240-pin DIMM can vary, but it always has 120 pins on the front & 120 pins on the back, for a total of 240. 240-pin DIMMs are Approx. 5.25 inches long & 1.18 inches high, though the heights can vary. While 240-pin DDR2 DIMMs, 184-pin DDR DIMMs, & 168-pin DIMMs are Approx. the same size, 240-pin DIMMs & 184-pin DIMMs have only one notch within the row of pins. The notch in a 240-pin DDR2 DIMM is closer toward the center of the module.