What distinguishes RDIMMs from LRDIMMs?

• A. A standard memory module with built-in error correction.
• B. Registered DIMMs buffer control signals for stability; Load-Reduced DIMMs reduce electrical load for larger capacities.
• C. Non-volatile DIMMs store data when power is off.
• D. High-density DIMMs use less electrical load.

Answer: (B)

The main distinction is how the memory module handles signaling and load on the memory bus. A registered DIMM includes a register that buffers the address, command, and control signals between the memory controller and the DRAM, which stabilizes timing and improves reliability when using many DIMMs or higher speeds. A load-reduced DIMM uses an isolation buffer to offload part of the electrical load from the memory controller, allowing larger memory densities per channel by reducing the bus capacitance the controller sees. So RDIMMs focus on signal stability with a buffer; LRDIMMs focus on reducing electrical load to enable higher capacities. The other options don’t capture this distinction: ECC/non-ECC isn’t what separates them, non-volatile DIMMs are a different category, and density alone isn’t the defining factor.