DDR2 SDRAM

In information technologies we use the term DDR2 SDRAM for a Double Data Rate memory module of the second generation. This technology is used for high speed storage of the working data.

 History 
DDR2 was first made in 2001.

 Comparisons 
The main difference between DDR and DDR2 modules is that the bus on which the DDR2 memory modules are working is clocked at twice the speed of the memory cells. In practical terms we can say that four words of data can be transferred during one memory cell cycle. To sum it up DDR2 can effectively operate at twice the bus speed of DDR.

Specification standards
Chips and modules
For use in PCs, DDR2 SDRAM is supplied in DIMMs with 240 pins and a single locating notch.  DIMMs are identified by their peak transfer capacity (often called bandwidth).

Standard name Memory clock Cycle timeI/O Bus clockData transfers per second Module namePeak transfer rate DDR2-400   100 MHz  10 ns   200 MHz   400 Million  PC2-3200   3200 MB/s DDR2-533  133 MHz  7.5 ns  266 MHz  533 Million  PC2-4200   4266 MB/s DDR2-667  166 MHz  6 ns  333 MHz  667 Million  PC2-5300  5333 MB/s DDR2-800  200 MHz  5 ns  400 MHz  800 Million  PC2-6400  6400 MB/s DDR2-1066  266 MHz  3.75 ns  533 MHz  1066 Million  PC2-8500  8533 MB/s

Category:Computer memory

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