Expreview published a photo and benchmark results of the Radeon HD 4770 graphics card from Connect3D. This model has 640 stream processors, 128-bit memory bus, 750MHz core and 512MB GDDR5 memory clocked at 3200MHz. The GPU is made on a 40nm process and the card has a TDP of just 80W.
Here's some info about how the card performance in 3DMark Vantage on a Core i7 system. As we have already heard earlier this year, the Radeon HD 4770 is just a little bit slower than the Radeon HD 4850.
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%.