DDR Memory is a type of computer memory that's initials stand for Double Data Rate Memory. DDR Memory is the computer's primary working memory that stores all of its program instructions, as well as, data used by the CPU (Central Processing Unit). It is called "Double" because it is intended to work through two operations per clock cycle.
A clock cycle is the time between two pulses of the oscillator (electronic device) that sets the tempo of the computers processor. The number of these pulses per second is called the clock speed. The clock speed is usually measured in MHz or GHz.
DDR Memory has higher transfer rates than SDRAM. This is because there is more control of the timing of the electrical data and the clock signals for the computer's information. DDR memory belongs to the Dual In-line Memory Module or DIMM.
In definition, a DIMM is a small circuit board that holds memory chips inside the computers motherboard. DIMM is an upgraded version of a SIMM (Single In-line Memory Module). Two SIMM cards equal one DIMM cards, which are typically used to date.
The modules of DDR Memory are set up that there is one notch on the connecting side and two notches on the side that attached to your PC's motherboard. DDR Memory comes in single-sided and double-sided chips.
There are three major types of DDR Memory, DDR or DDR1, DDR2, and DDR3. DDR Memory has speeds ranging from 200MHz all the way up to 400MHz.