Memory module

Later, memory modules were standardized by organizations such as JEDEC and could be used in any system designed to use them.

Distinguishing characteristics of computer memory modules include voltage, capacity, speed (i.e., bit rate), and form factor.

[2] However, since SRAM has high leakage power and low density, die-stacked DRAM has recently been used for designing multi-megabyte sized processor caches.

Dynamic random access memory is produced as integrated circuits (ICs) bonded and mounted into plastic packages with metal pins for connection to control signals and buses.

In early use individual DRAM ICs were usually either installed directly to the motherboard or on ISA expansion cards; later they were assembled into multi-chip plug-in modules (DIMMs, SIMMs, etc.).

Two types of DIMMs (dual in-line memory modules): a 168-pin SDRAM module (top) and a 184-pin DDR SDRAM module (bottom).
Memory modules of SK Hynix
A 256 x 4 Kibit 20-pin DIP DRAM on an early PC memory card, usually Industry Standard Architecture
Common DRAM packages. From top to bottom: DIP, SIPP, SIMM (30‑pin), SIMM (72‑pin), DIMM (168‑pin), DDR DIMM (184‑pin).
16 GiB DDR4-2666 288-pin 1.2 V UDIMMs