Over 100% everything is a bonus. Enjoy it while I can.

If you calculate resell price to ROI it is lot quicker, that's true. But before you have the money in your wallet, you better calculate with everything you spent.

My friend built a 3 card rig that capable of 4,5MH. It was around $4000. Those 7990s won't be very popular if GPU mining goes boom. That's a really nice rig but he needs to reach $4000 to make profits. Of course if he sell them he get back some of the money, but he needs them if he wants to make money. That's why I call them bonus.

Not to mention that rig has a lot of problems... PSUs can't keep up and die, cables fry, etc...