Retail comes with 3 year AMD warranty, while OEM usually only have 1 year. Retail also come with a heatsink and fan... Sure, not a great heatsink and fan, but it does a good job of keeping it cool. The one i got with my Thunderbird 750 keeps it running at around 50C.
...And where at buy.com do u see it as a retail box??? I dont see anything that would suggest to me that it is retail
...And I look again, and see the part # is D850BOX