A DIMM is a Dual Inline Memory Module. A DIMM is a small circuit board designed to hold a set of RAM chips. A DIMM has a 64-bit data bus, which allows DIMM's to be connected one at a time to a CPU with a 64-bit data bus. DIMM Sizes DIMM's are available in several different physical sizes. Contact Count Usage 72 SODIMM 144 SODIMM 168 SDRAM 184 DDR SDRAM 240 DDR2 SDRAM DIMM contacts are single sided, which means that a DIMM with 72 contacts will have 36 contacts on each side.
DIMM Types DIMM modules are sold according to clock speed (MHz), bus speed (mega-transfers per second), and transfer rate (megabytes per second. Standard SDR SDRAM DIMM's DIMM Module Chip Type Clock Speed Bus Speed Transfer Rate PC66 10ns 66 66 533 PC100 8ns 100 100 800 PC133 7.5/7ns 133 133 1,066 Standard DDR SDRAM DIMM's DIMM Module Chip Type Clock Speed Bus Speed Transfer Rate PC1600 DDR200 100 200 1,600 PC2100 DDR266 133 266 2,133 PC2400 DDR300 150 300 2,400 PC2700 DDR333 166 333 2,667 PC3000 DDR366 183 366 2,933 PC3200 DDR400 200 400 3,200 PC3500 DDR433 216 433 3,466 PC3700 DDR466 233 466 3,733 PC4000 DDR500 250 500 4,000 PC4300 DDR533 266 533 4,266 Standard DDR2 SDRAM DIMM's DIMM Module Chip Type Clock Speed Bus Speed Transfer Rate PC2-3200 DDR2-400 200 400 3,200 PC2-4300 DDR2-533 266 533 4,266 PC2-5400 DDR2-667 333 667 5,333 PC2-6400 DDR2-800 400 800 6,400 168 Contact DIMM's The earliest DIMM's were of the 168 contact variety. These DIMM's have come in a variety of configurations. It is possible to determine the configuration of the DIMM by examining the placement of notches on the bottom of the DIMM. DIMM Notch Key One Position Meaning 1 Reserved 2 Buffered 3 Unbuffered DIMM Notch Key Two Position Meaning 1 5.
0V 2 3.3V 3 Reserved.
Kyle Richards writes on topics such as DIMM , RAM and SRAM for The Tech FAQ.
