Overclocking

The Radeon HD3850 does support voltage control, but the available range is very limited. Depending on the board design it goes from 1.0V to 1.3V in seven steps. Since most cards have their default voltage at over 1.2V already, there is not much to be gained from overvolting. A future ATITool version will support voltage changes on both HD 3850 and HD 3870.

We used ATITool to manually search for the maximum core and memory clocks.



The final overclocks of our card are 708 MHz Core (1 % overclock) and 864 MHz Memory (2 % overclock). This is very very poor, but only those clocks were actually benchmark stable. We could set much higher clocks but at some point the benchmarks always crashed. Also you have to consider these overclock in relation to the AMD reference design clocks, then the overclocks are 6 % and 4 %, still not that much I must say.
One possible explanation for our low overclocks could be that we had a "Sample" GPU on our board. These are the first GPUs from the production ramp up to be shipped outside AMD, so the binning is more relaxed to get as many GPUs out as possible.


The Radeon HD 3850 X-Turbo III uses a temperature controlled fan which ramps up speed as temperatures rise. As we can see this is working fine, even under load the temperatures stay well below 65°.