We performed a typical trial-error testing procedure in order to see the overclocking margins of the Gainward HD4870 1GB GS.

Possibly the easiest way to overclock an AMD graphics card is to use the ATI Overdrive function. The " Auto-Tune" function gives us some quick numbers:

What we got from ATI's Auto Tune function is rather limited since the GPU marginally reached the 780MHz, while Memory went up to just 1040MHz.

We also tried Gainward's Expert Utility for overclocking but still, the results where the same:

For higher overclocking, you have to use the latest RivaTuner software ( v2.11). Using the software's sliders we pushed the frequencies high enough, as you can see in the table below.

Don't forget to test the stability of the graphics cards each time you change a frequency, by running nine (9) rounds of Crysis.

The overclocking performance was average. We got a stable system at 822/1092MHz. These frequencies are probably translated to small improvements in the performance with games/applications.