The Radeon HD 6850 is situated mid-way between the Radeon HD 5770 (renamed as the Radeon HD 6770) and the Radeon HD 6870. It’s closer to the first in terms of processing power but closer to the second in terms of memory bandwidth.
GDDR5 Hynix 1.25 GHz for everyone
All the Radeon HD 6850s that we tested were equipped with Hynix GDDR5 certified at 1.25 GHz although it’s only clocked at 1 GHz on models that use the reference clocks and 1.1 GHz on overclocked models. We imagine that this is because AMD has simplified the Barts GPU memory controller, stopping it from taking advantage of higher clocks. We will however check to see if there’s a margin for overclocking.
Remember that these clocks represent those at which commands are sent to the memory, but that in the case of GDDR5 data transits at twice the frequency, something we include in our spec tables so as to allow direct comparison with GDDR3.