Difference between DDR2 and DDR3

DDR2: DDR2 stands for Double Data Rate 2 is the 2nd version of DDR. Memory DDR2 is more faster and efficient than SSR because of its elevated design. It transfers data 400-1066 mhz. clock rate. The key change in DDR2 is to the length of prefect. The reteach lenth is four bits for each bit in a word where DDR memory uses two bits for every bit DDR2 is not for word compatible with the DDR3. DDR2 uses 240 pianism DIM for the computer and for the laptop it uses 200 pin is so-SIMM. So SIMM is the smaller version of DIMM.

DDR3: DDR3 stands for Double Data Rate 3. It is the extended version of DDR2. It is quite similar to DDR2 but uses less power and data transfer rate is two times faster than DDR2. It can transfer data up to 6400 mbps. The prefetch length is 8 bit for each bit in a word. DDR3 is also used 240 pins in DIMM. But is totally incompatible with DDR2 because of its different notched kye. So upgrading to DDR3 world cost a lot of money. It you want to use DDR3 Ram instead of you DDR2 RAM then you need to change the motherboard and even your processor. DDR3 also expensive than DDR2 RAM.