Sapphire Radeon HD 6990 4GB Graphics Card

Overclocking
The 6990 already has a preset overclocking feature when using the AUSUM function. This automatically clocks the card from 830MHz to 880MHz but we wanted to see how far we could push it.

To find the maximum overclock, we used MSI Afterburner to increase the clock speeds by 10MHz at a time, whilst relying on GPU-Z for clarification of the speeds and Furmark to test stability.

The results that we obtain can only be used as a guideline as to what this range of cards can do. Obviously every card has a different core among other vital parts, and therefore each card will give slightly varied results.

The overclocks that we were able to obtain at full stability were 960MHz Core/GPU clock and 1480MHz Memory clock which from the stock 830MHz and pre-overclocked stock 880MHZ, the results were quite impressive giving clear headroom on top of the extra speeds that the card gives by using the AUSUM feature. With these overclocks the fan was working overtime and the noise from it was something we couldn’t wait to turn off.