VRR vs. battery life (13th gen)

[meeotch]

Anyone have an educated guess (or better, test results) as to how much difference in battery life the VRR OLED display (30-120Hz, I believe) will make over the non-VRR OLED, which is locked to 60 or 120Hz?

notebookcheck reported 10+ hours on their web surfing test on the non-VRR display, but were only able to get there by dropping the refresh to 60Hz, or putting the browser in dark mode:
https://www.notebookcheck.net/Lenovo-Th ... #c12342523

To get the VRR display you have to go CTO, which explodes the price on CPU/RAM/SSD vs. the discounted pre-built options. (I don't strongly care about VRR by itself, but do strongly care about battery life.)