/dɪm/
n. — "64-bit RAM sticks plugging into motherboard slots."
DIMM (Dual In-line Memory Module) packages multiple DRAM chips on a PCB with 288-pin (desktop) or 260-pin (laptop SO-DIMM) edge connector providing 64-bit data path for DDR memory, succeeding SIMM's 32-bit half-width design. UDIMM (unbuffered), RDIMM (registered), LRDIMM (load-reduced) variants support desktop/server scaling, with DDR5 DIMMs integrating PMIC and dual 32-bit subchannels per module for 4800-8800MT/s operation.
Key characteristics and concepts include:
- 288-pin DDR4/DDR5 desktop form factor vs 260-pin SO-DIMM laptops, both delivering x64/x72 data paths for non-ECC/ECC.
- Rank organization (single/dual/quad) multiplying banks across module, critical for interleaving in multi-channel DDR controllers.
- PMIC integration in DDR5 DIMMs delivering clean 1.1V rails, mocking discrete motherboard regulation.
- SPD EEPROM autoconfiguring speed/timings via I2C during POST, preventing manual BIOS roulette.
In dual-channel desktop, two DDR5 DIMMs interleave rank accesses across 128-bit bus, PMIC stabilizes rails during burst writes while SPD reports CL=40-tRCD=36 specs to IMC.
An intuition anchor is to picture DIMM as a 64-lane highway offramp: multiple DRAM chips in parallel formation, plugging motherboard's memory slot to flood CPU with sequential data bursts.