Q. What are the differences between OEM and Retail versions of processors?
A. OEM = Original Equipment Manufacturer = a company that makes/markets computers (and parts), etc. which include parts made by other companies, and not the “original” manufacturer as OEM implies, just masquerading as one. OEM processors are earmarked for companies that build computers; Retail processors are packaged for store shelves and sold mainly to end-users. I buy both kinds. Retail (or "boxed retail," "PIB," "Processor in a Box") versions usually include a heatsink-fan (which may or may not be already mounted on the processor), user instructions, warrantee, etc. and OEM versions do not. See http://duxcw.com/digest/Howto/cpu/socka/1.html for more info on OEM and Retail processors, especially regarding heatsink-fans.