Don't qoute me on this but I believe OEM simply means the product doesn't come wiht the retail box, manuals, or warranty. If it were be I wouldn't go with OEM becuase for a little more money you get the manuals, and the security of your product being backed by a warranty. For example, An OEM AMD 3400 proccessor is 404$ while a regular one is 416$. IMO it's worth the extra. Keep posting if you have any more questions!