Small Outline Dual In-Line Memory Module is referred to as SO-DIMM. The capacity of the memory units is unimportant because RAM processors can fit in most desktop PCs with ease. The capacity of the RAM units counts a lot with computers, though. The dimensions of each component are important because computers are intended to be as compact and lightweight as feasible. Large Memory processors frequently do not fit into the general laptop design because laptop components are actually so closely packed together. Because of this, SO-DIMMs were developed.

A SO-DIMM is about 50 percent shorter than a DIMM of the same capacity. This gives designers of the memory ports for computers more freedom. In many computers, the SO-DIMMs are located in a user-accessible area, making it simple to update the computer's Memory. This type of architecture would be more challenging to implement and probably result in the notebook becoming larger if the Memory processors were full capacity DIMMs.

The first SO-DIMMs allowed 32-bit data transmissions and had 72 pins (or connections). However, contemporary SO-DIMMs usually have 144 ports, enabling the same 64-bit transfers as a standard capacity DIMM. Although desktop computers with compact form factors also use SO-DIMMs to decrease total case area, SO-DIMMs are mainly used in notebooks. Regular DIMMs are usually used because they are a more affordable option when capacity is not a concern.