small outline dual inline memory module.

This is a small form factor DIMM that is designed for use in laptops, graphics cards and other devices that require a smaller than normal DIMM. The SO-DIMM allowed for an easily interchangeable SDRAM module for small form factor devices, replacing numerous proprietary laptop memory standards.

Small Outline Dual In-Line Memory Module: a small version of a DIMM used commonly in notebook computers. Whereas a full-size DIMM has 168 pins and can support 64-bit transfers, and SO DIMM has only 72 pins and can support only 32-bit transfers. In this respect, it is more like a SIMM, except that it is smaller.