Answer:
DDR3 SDRAM having twice rate of data transferring as compared to DDR2 SDRAM both have 240 pin connection. DDR3 memory power consumption is 40 % less as compared to DDR2. both are transfers data on a 64 data bits wide bus. The physical difference occur in both type a cut is present at bottom along pin in DDR2 it is occur probably in center and In DDR3 it is occur at left through center.