dragoon42 is correct... sometimes you get a downgraded part (lower clocks, no VIVO, etc...)... plus no warranty... plus no third-party software... pluse no shiney colorful new box to put up next to your l33t case so your friends can oogle at it and say "ooooohhhh... shiney... can i hold it..."
EDIT: newegg.com might also carry the retail version for like $20-$50 bucks more... read the details...