What's the most common type of RAM today:
SDRAM: Synchronous dynamic random access memory takes advantage of the burst mode concept to greatly improve performance. It does this by staying on the row containing the requested bit and moving rapidly through the columns, reading each bit as it goes. The idea is that most of the time the data needed by the CPU will be in sequence. SDRAM is about five percent faster than EDO RAM and is the most common form in desktops today. Maximum transfer rate to L2 cache is approximately 528 MBps.
DDR SDRAM:Double data rate (DDR) synchronous dynamic RAM is just like SDRAM except that is has higher bandwidth, meaning greater speed. Maximum transfer rate to L2 cache is approximately 1,064 MBps (for DDR SDRAM 133 MHZ).
The DDR2 memory.
What is DDR2?
Stands for "Double Data Rate 2." DDR2 RAM is an improved version of DDR memory that is faster and more efficient. Like standard DDR memory, DDR2 memory can send data on both the rising and falling edges of the processor's clock cycles. This nearly doubles the amount of work the RAM can do in a given amount of time. DDR and DDR2 are also both types of SDRAM, which allows them to run faster than conventional memory.
While DDR and DDR2 have many similarities, DDR2 RAM uses a different design than DDR memory. The improved design allows DDR2 RAM to run faster than standard DDR memory. The modified design also gives the RAM more bandwidth, which means more data can be passed through the RAM chip at one time. This increases the efficiency of the memory. Since DDR2 runs more efficiently than standard DDR memory, it actually uses less power than DDR memory, even though it runs faster. The only downside of DDR2 memory is that it is not compatible with standard DDR slots. So make sure your computer supports DDR2 RAM before upgrading your memory.
*update :The latest development now is DDR3.while the DDR2 is the trend today.
