If you'd like i'll pop my 5770 in and run and show the benchmarks, a 4890 is about 10-15% increase over a 5770. This card still retails for 200$ by vendors that sell it, and im only looking for around 90-100 or so lol
the 5770 has been shown is most benchmarks at the 4850 bracket, but 4870 bracket when oc'd.