The difference between oem and retail is the fact that with retail you can usually send the product back to the manufacturer for a longer period of time. With oem it varies but with cpu's its usually dependent on the place of purchase unless you get a written warrenty with the product. It depends what company you deal with also. I only buy oem if there is a manufacturer warrenty with the product and always buy retail cpu's. As long as there is a warrenty though you should have no problems.