kettu :
First question:
A strategy game like Civ V is more CPU limited than GPU limited.
Second question:
Slight variations between test platforms + statistical variation would be my guess.
The thing is, going from 1024x768, 0AA to 2560x1600 4xAA = identical performance in every test .... not a chance
same results on starcraft 2 and skyrim
According to toms, skyrim at 1280x1024 no aa reaches 122 fps and 65 fps at 1900x1200 4xaa on the 6970 but techpowerup gets identical results and again slower with the 7970 only achieving 56fps at all resolutons
So seeing results that are clearly incorrect, how reliable is the entire article....
In my opinion ... not very reliable, but it is a good theory to test.