house70 :
Even if you got the game via a video card promotion, it doesn't mean you could not play the game using a different card. It's the same game as retail.
If you're using the same steam account, you'll be able to install it on your other PC (with the I3 and the 7730) without using up the second install code. However, for obvious reasons, you'll only be able to play games tied to that account on one P.C. at a time. If you're, say, using a different P.C. at two different locations and not sharing either P.C., this might be your solution.