1GB Ballistix DDR2 PC2-8500 (1066MHz) Memory Module, 5-5-5-15, Unbuffered, Non-ECC, 2.0V, 128Meg x 64, 240-pin DIMM. The Ballistix line is specifically built for performance enthusiasts who want to push the performance envelope without worrying about data loss or corruption, mysterious intermittent errors and display problems, or worse -- the dreaded BSOD! The Ballistix line of high-performance memory modules features advanced speed grades, low latencies, and integrated aluminum heat spreaders. A Ballistix dual inline memory module (DIMM) consists of a number of memory components that are attached to a black printed circuit board. The gold pins on the bottom of the DIMM provide a connection between the module and a socket on a larger printed circuit board. The pins on the front and back of a DIMM are not connected to each other. Ballistix 240-pin DIMMs are used to provide DDR2 SDRAM memory for desktop computers. DDR2 is a leading-edge generation of memory with an improved architecture that allows it to transmit data very fast. To use DDR2 memory, your system motherboard must have 240-pin DIMM slots and 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 Ballistix 240-pin DIMM can vary, but it always has 120 pins on the front and 120 pins on the back, for a total of 240. Ballistix 240-pin DIMMs are approximately 5.25 inches long and 1.18 inches high, though the heights can vary. While 240-pin DDR2 DIMMs, 184-pin DDR DIMMs, and 168-pin DIMMs are approximately the same size, 240-pin DIMMs and 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.