When it came to overclocking, we didn't expect the results to be world class considering there was no way to reduce the core temperature while increasing the GPU clock speed. Still, since the HD 7750 is built on a 28nm node, the core is going to have more overclocking headroom than the previous generation 40nm graphics cards.
In our labs, we could increase the GPU clock speed of the Sapphire HD 7750 Ultimate by just under 12%, which isn't going to produce results that are drastically different from the reference clock speeds. The memory boost also capped out right around 10%, meaning we were able to increase the GDDR5 memory frequency up to 1271MHz in total. That is an increase of 146MHz in comparison to the reference memory clock, increasing the bandwidth to 81.3GB/s. While these results are not too impressive, the higher clock speeds help yield better performance without dramatically increasing the power consumption.