page_title: Memory module
section_title: General DRAM formats
hierarchical_section_title: Memory module / General DRAM formats
context_page_description: In computing, a memory module or ram stick is a printed circuit board on which memory integrated circuits are mounted. Memory modules permit easy installation and replacement in electronic systems, especially computers such as personal computers, workstations, and servers. The first memory modules were proprietary designs that were specific to a model of computer from a specific manufacturer. Later, memory modules were standardized by organizations such as JEDEC and could be used in any system designed to use them.
  Types of memory module include:
  TransFlash Memory Module
  SIMM, a single in-line memory module
  DIMM, dual in-line memory module
  Rambus memory modules are a subset of DIMMs, but are normally referred to as RIMMs
  SO-DIMM, small outline DIMM, a smaller version of the DIMM, used in laptops
  Distinguishing characteristics of computer memory modules include voltage, capacity, speed, and form factor.
  For economic reasons, the large memories found in personal computers, workstations, and non-handheld game-consoles normally consist of dynamic RAM. Other parts of the computer, such as cache memories normally use static RAM.
context_section_description: 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.). Some standard module types are:
  DRAM chip (Integrated Circuit or IC)
  Dual in-line Package (DIP/DIL)
  Zig-zag in-line package (ZIP)
  DRAM (memory) modules
  Single In-line Pin Package (SIPP)
  Single In-line Memory Module (SIMM)
  Dual In-line Memory Module (DIMM)
  Rambus In-line Memory Module (RIMM), technically DIMMs but called RIMMs due to their proprietary slot.
  Small outline DIMM (SO-DIMM), about half the size of regular DIMMs, are mostly used in notebooks, small footprint PCs (such as Mini-ITX motherboards), upgradable office printers and networking hardware like routers.
  Small outline RIMM (SO-RIMM). Smaller version of the RIMM, used in laptops. Technically SO-DIMMs but called SO-RIMMs due to their proprietary slot.
  Stacked vs. non-stacked RAM modules
  Stacked RAM modules contain two or more RAM chips stacked on top of each other. This allows large modules to be manufactured using cheaper low density wafers. Stacked chip modules draw more power, and tend to run hotter than non-stacked modules.  Stacked modules can be packaged using the older TSOP or the newer BGA style IC chips. Silicon dies connected with older wire bonding or newer TSV.
  Several proposed stacked RAM approaches exist, with TSV and much wider interfaces, including Wide I/O, Wide I/O 2, Hybrid Memory Cube and High Bandwidth Memory.
caption: Common DRAM packages. From top to bottom: DIP, SIPP, SIMM (30‑pin), SIMM (72‑pin), DIMM (168‑pin), DDR DIMM (184‑pin).
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