Yea, that requires a bigger investment though. Someone is sellin 2 7970s for $75...
yeah ok, but remember this
the 7970 when you sell it again it will be worth $50, if you can ever dream to sell it again(no one will buy it)
a 480 can still be worth $200 in 6 months or more, that is the big difference
you only need to roi on the difference between the purchase price and the resale price, not the whole initial investment