Would it be a stupid purchase,to buy a nvidia 480 gtx .i see some for 299.with also a 50 dollar coupon to make it 249. i was lookin at the 570 they seem to be near par with eachother.i currently have a 4890.its been doing great for me.just thinking about dx 11.not sure if its even worth the upgrade.figured maybe its time to up just alittle to a 480 or something. or maybe get 2 cheap cards to crossfire or sli.