how to identify DDR1 RAM and DDR2 RAM

how to identify DDR1 and DDR2

1. Mostly DDR RAM 1 will have big chips on RAM Board where compare to DDR2
2.  Pins missing both either direction at RAM notch in DDR2 and DDR1 will have one side pins are missing.
3. DDR RAM size is 15cm, DDR1 will have notch at the centre of the length i.e., 7.5 cm and DDR2 7cm

-This is DDR2

This is DDR 1