It should be the same brand new CPU model.
OEM - short warranty, you supply the HSF and thermal compound/pad, no fancy box
Retail - longer warranty, includes HSF with thermal compound/pad, fancy box
I had bought e6600 processor with ECS P965 mobo for $299 as a combo deal from Frys.
The cpu was not boxed but came in a simple thin plastic case.
I checked other places and notice that e6600 is never less that $319 and they show a intel blue box.
What is the difference between the intel box and the clear plastic case from Frys?