SIMM (Single Inline Memory Module)

• 30 pin - 8 bit data width
• 72 pin - 32 bit data width
• Outdated

DIMM (Dual Inline Memory Module)

• 133mm x 38mm (Approx. 5 1/4 x 1 1/2 inches)
• 64 bit data width
• Package used for:
  • SDRAM - 168 pins
  • DDR RAM - 184 pins
  • DDR2 RAM - 240 pins

RIMM (Rambus Inline Memory Module)

• Desktop version - 184 pins
• Laptop Version - 160 pins

SO-DIMM (Small Outline DIMM)

• 68mm x 32mm (Approx. 2 11/16 x 1 1/4 inches)
• Primary use in laptops
• 72, 144, and 200 pins

Micro-DIMM

• 45mm x 30mm (Approx. 1 3/4 x 1 3/8 inches)
• 64 bit data width
• Primary use in laptops
• 144 and 172 pins