Stands for "Double Data Rate Type 3." DDR3 is a type of SDRAM that is used for system memory. It is available in both DIMM and SO-DIMM form factors.
DDR3 RAM is similar to DDR2 RAM, but uses roughly 30% less power and can transfer data twice as fast. While DDR2 memory can transfer data at up to 3200 MBps (megabytes per second), DDR3 memory supports maximum data transfer rates of 6400 MBps. This means computers with DDR3 memory can transfer data to and from the CPU much faster than systems with DDR2 RAM. The faster memory speed prevents bottlenecks, especially when processing large amounts of data. Therefore, if two computers have the same processor clock speed, but different types of memory, the computer with DDR3 memory may perform faster than the computer with DDR2 memory.
DDR3 memory modules look similar to DDR and DDR2 chips, but the gap that separates the two sets of pins on the bottom of each module is in a different location. This prevents the RAM chip from being installed in a slot that does not support DDR3 RAM. Therefore, when upgrading your computer's memory, make sure you get the appropriate type of memory for your computer.