Performance Summary
The graphs on this page show a combined performance summary of all tests and resolutions from previous pages. Each graph shows the tested card as 100% and all other cards' performance as relative to it. A sixth graph summarizes all tests in all resolutions to calculate the total relative performance of the review sample.
The relative improvements for each card are:
HD 7750: +4%
HD 7770: +5%
HD 7850: +4%
HD 7870: +10%
HD 7950: +7%
HD 7970: +7%
HD 7970 GHz: +7%
Personal opinion:
pretty nice performance increase by just pure driver oh wow! 
Source