According to associate the default frequencies range of RV770 core will be less than the expected value. The Radeon HD 4850 will work on close to the Radeon HD 3850 frequencies, approximately 668/1656 MHz. core Frequency for radeon HD 4870 will not exceed 800 MHz.
With the use of air cooling it was possible to overclock the RV770 to the frequency more than 1 GHz. This Chip will be released on the previous 55 nm technical process, and core area in comparison with RV670 will increase approximately by 35% - to 256 sq. mm.