Only counted average frame rates at the Full HD (1080p) resolution.
There are many launch reviews who's using factory overclocked cards for the GeForce GTX 1660 Ti and the Radeon RX 590. All following values with an asterisk (*) comes from factory overclocked cards.
There are even reviews out there who forget to mention the use of factory overclocked cards in their benchmark diagrams (means triple check everything to be sure).
For the average of all reviews the factory overclocked cards was normalized to the reference clocks (more on the performance effect of factory overclocked cards for the GeForce GTX 1660 Ti here).
The average performance is weighted in favor of these reviews using reference clocks.