OEM stands for Original Equipment Manufacturer.  OEM memory means that the semiconductor/PC company that carries the memory module manufactures and assembles the memory chips and all other memory components along with the PCB unto which the components are mounted.  These memory modules are the ones originally designed and installed to work on specific systems.  The largest PC companies such as IBM, Compaq/HP, Dell, Gateway, Apple and Toshiba use OEM memory in their systems.  eFetcher guarantees 100% compatibility with OEM memory.