A:AnswerThis card is identical to the 08G-P4-5671-KR (I have both). The KB just means that it is for Best Buy.... meaning you can't price match other retailers, or attempt to return a card purchased elsewhere here.
A:AnswerDepends on your power supply. Your motherboard and case should be able to handle it, but you'll want to make sure that your power supply has enough wattage to keep it all running.