This has to be the largest roundup that I have ever put together. Out of 52 reviews, 46 of them had overclocking data. It is important to note that at the bottom of the list is a Sapphire HD 7950 OC CrossFire result from Hexus. Both cards were set to 900/6,000 in that case. If a review stated that the voltage was kept at stock levels, or if I could see that the voltage was unchanged (from a screenshot) then I wrote 'Stock' in the table. If they did not mention any voltage changes, I entered question marks in the voltage cell for that card.
The winners here were Earthdog at Overclockers.com with a massive core speed of 1,229MHz (that is a 53.6% increase!) and W1zzard from TechPowerUp with a huge memory speed of 7,140Mhz (a 43% increase!). The man with the highest core and memory clocks was James Prior from Rage3D.com.
The average overclock for the HD 7950 was 1,081/6,104 which is pretty damn close to the HD 7970's averages of 1,095/6,185. The average increase for the HD 7950 is waaay above the average increase for its big brother. We are talking 35.14%/22.08% for the HD 7950 and 18.33%/12.45% for the HD 7970. Wow!