Here are the numbers:
GPUReview's HD 7750 overclocking roundup!
Posted By: Steve McBarnes - 11:59:11 Fri, February 17, 2012
On the HD 7750 side of the fence we have 19 reviews and only 11 overclocking results. The HD 7750 is not as overclockable as its bigger brother because it does not have a power connector to receive additional power from your PSU. This also does not allow you to increase the voltage of the card.