Dram : The Difference Between Ddr1 & Ddr2
About DDR1.
DDR SDRAM or double-data-rate synchronous dynamic random access memory is a class of memory integrated circuit used in computers. It achieves greater bandwidth than the preceding single-data-rate SDRAM by transferring data on the rising and falling edges of the clock signal (double pumped). Effectively, it nearly doubles the transfer rate without increasing the frequency of the front side bus. Thus a 100 MHz DDR system has an effective clock rate of 200 MHz when compared to equivalent SDR SDRAM, the "SDR" being a retrospective designation.
With data being transferred 64 bits at a time DDR RAM gives a transfer rate of [mbcr x 2 x 64] / 8; annotated it looks like this: (memory bus clock rate) × 2 (for dual rate) × 64 (number of bits transferred) / 8 (number of bits/byte). Thus with a bus frequency of 100 MHz, DDR-SDRAM gives a max transfer rate of 1600 MB/s.JEDEC has set standards for speeds of DDR SDRAM, divided into two parts: The first specification is for memory chips and the second is for memory modules.
About DDR2
In electronic engineering, double-data-rate two synchronous dynamic random access memory (DDR2 SDRAM) is a random access memory technology used for high speed storage of the working data of a computer or other digital electronic device.
It is a part of the SDRAM (synchronous dynamic random access memory) family of technologies, which is one of many DRAM (dynamic random access memory) implementations, and is an evolutionary improvement over its predecessor, DDR SDRAM (double-data-rate synchronous dynamic random access memory).
Its primary benefit is the ability to run its bus at twice the speed of the memory cells it contains, thus enabling faster bus speeds and higher peak throughputs than earlier technologies. This is achieved at the cost of higher latency.
Like all SDRAM implementations, DDR2 stores memory in memory cells that are activated with the use of a clock signal to synchronize their operation with an external data bus. Like DDR before it, DDR2 cells transfer data both on the rising and falling edge of the clock (a technique called double pumping). The key difference between DDR and DDR2 is that in DDR2 the bus is clocked at twice the speed of the memory cells, so four words of data can be transferred per memory cell cycle. Thus, without speeding up the memory cells themselves, DDR2 can effectively operate at twice the bus speed of DDR.
The author is an expert writer with over 10 years of marketing experience in the field of computer memory. Currently, he is working for Om Nanotech Pvt. Ltd. He is writing on various computer products like RAMS, USB drives, Flash drives, Web cam and other computer hardware.
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