Different between SD,DDR 1,2,3 and DDR4 RAM:

1-SD RAM

• 168 Pins
• 3.3v
• Double cut
• 66-133 MHz FSB

2-DDR1

• 184 Pins
• 2.5v
• Single cut
• 200-400 MHz FSB

3-DDR2

• 240 Pins
• 1.8v
• Single cut
• 400-800 MHz FSB

4-DDR3

• 240 Pins
• 1.5v
• Single cut
• 800-2133 Mhz FSB

5-DDR4

• 240/244/288 Pins
• 1.2v
• Single cut
• 2133-4266 MHz FSB