Lecture Notes: Random Access Memory (RAM)

Introduction to RAM

• RAM stands for Random Access Memory.
• It's used in personal computers for high-speed temporary storage.
• Not to be confused with SSD or hard drive storage.
• Essential for loading applications and documents.

Memory Modules

• DIMMs: Dual Inline Memory Modules.
  • Differing connectors on each side.
  • Data is transferred with a 64-bit width.
  • Installed by pressing into slots with clips to secure.
• SODIMMs: Small Outline DIMMs.
  • Used in laptops due to smaller size.
  • Half the width of standard DIMMs.
  • Also installed by slotting and locking in place.

DRAM - Dynamic Random Access Memory

• DRAM: Requires constant refreshing to retain data.
• Random Access: Can access any data location directly.

Synchronous Operation

• Memory is synchronized with a clock on the system.
• Clock cycles regulate data transfer in and out.

Memory Types and Compatibility

• Notches: Prevent installation of incompatible memory types.
  • Different types of slots (e.g., DDR2, DDR3) prevent incorrect installations.

Evolution of Memory Types

• SDRAM: Older Single Data Rate memory.
  • Transfers one bit per clock cycle.
• DDR - Double Data Rate: Modern systems use DDR.
  • DDR3: Doubled speed over DDR2, supports up to 16GB per module.
  • DDR4: Increased speeds, supports up to 64GB per module.
  • DDR5: Faster than DDR4 with the same 64GB module capacity, requires specific motherboard support.

Compatibility Notes

• No backward compatibility among DDR versions.
• Ensure motherboard support for the memory type you intend to use.