Benchmarks for the HD4770 are slowly trickling in, but first to show some is expreview with some preliminary 3dmark results, compared against an HD4850.
As we can see, Radeon HD 4770 shows a 3DMark Vantage/GPU Score of P8086/6639, compared with P8367/6891 found on HD 4850, which means HD 4770 only lags behind HD 4850 by 3.47/3.79%.
via First Radeon HD 4770 Benchmark Goes Alive – Expreview.com.
