1, working voltage of DDRI is 2.5V, and working voltage of DDRII is1.8v.

2. The PIN of DDRI is 180 pin, and the pin of DDR II is 220pin.

3. The main frequency of 3.DDRI is 266/333/400, and that of DDRII is 400/533/667MHz.

The highest frequency of DDR 1 is 400, DDR2 is 800, and DDR3 is higher. Different types of the three cannot be mixed.

Memory chips of the same type with different frequencies can be mixed.

For example, 333 of DDR 1 and 400 of DDR 1 can be mixed.

The biggest difference between DDR 1 and DDR2 DDR3 is:

DDR2 DDR3 has a built-in programmable terminator.

The terminator is used to shape the stored signal. If the terminator is far away from the memory port, the long conductor will cause the signal to oscillate again because of the inductance of the conductor (the conductor is the inductance, please read high school physics if you don't believe me). Obviously, the integrated terminator reduces the lead inductance to the limit. Insert one memory, insert two memories. In various states such as transmission and reception, the optimal value of the required terminal resistance is not constant. Programmable terminator can make the terminator resistance in a better state.

The improvement of DDR3 to DDR2 increases the correction function of terminator resistance, which makes the signal shaping ability of terminator stronger. A memory channel has only one slot. In this way, the so-called point-to-point is realized. This can greatly improve the integrity of the signal. The port frequency of DDR2 is higher than that of DDR 1, and the port frequency of DDR3 is a flight of stairs. Because of the upgrade and improvement of I/O circuit. Timing is to solve the problem of low memory core frequency.