SO-DIMM


A SO-DIMM, SODIMM, or small outline dual in-line memory module, is a type of computer memory built using integrated circuits. SO-DIMMs are a smaller alternative to a DIMM, being roughly half the size of regular DIMMs.
SO-DIMMs are often used in systems that have limited space, which include laptops, notebooks, small-footprint personal computers such as those based on Mini-ITX motherboards, high-end upgradable office printers, and networking hardware such as routers and NAS devices.

Visual identification

Most types of SO-DIMMs can be recognized visually by the distinctive notches that "key" them for different applications:
The 200-pin SO-DIMM can be of the types DDR and DDR2. In both cases the notch is located at one fifth of the board length, but in DDR2 the notch is located slightly closer to the center of the board. These two types of memory are not interchangeable. The different notch locations are designed to prevent cross-installation, aiding at the same time in visually identifying 200-pin SO-DIMM modules.
This variance is designed to prevent coupling of memory and controllers of different DDR generations due to electrical incompatibility. DDR SO-DIMMs operate at 2.5 V while DDR2 SO-DIMMs operate at 1.8 V.

Variants of DDR3 SO-DIMMs

These modules, while using the same physical layout, may differ in the specified voltage 1.5 or 1.35 volts. The lower voltage modules are sometimes, but not always, identified as DDR3L see also DDR3 SDRAM.

General characteristics

200-pin and 204-pin SO-DIMMs are long, wide, having a maximum total depth of.
SO-DIMMs are nearly equal in power and voltage rating to DIMMs; SO-DIMM technology does not mean lower performance compared to larger DIMMs. For example, DDR3 SO-DIMMs provide clock speeds such as 533 MHz, CAS latencies such as 7, and higher capacities such as 4 GB per module.
DDR2 SO-DIMM memory modules commonly have clock speeds from 200 MHz upward. 204-pin SO-DIMMs can also contain DDR3 SDRAM, with specifications such as PC3-6400, PC3-8500, PC3-10600, PC3-14900 and PC3-17000. 260-pin UniDIMMs contain DDR3 or DDR4 SDRAM depending on configuration. Some SO-DIMMs provide ECC functionality; unbuffered ECC SO-DIMMs are called SO-CDIMMs.