Worse performance when using high refresh rate

TL;DR:

At 60 Hz, Shadow of the Tomb Raider benchmark: 46 FPS
At 120 Hz, Shadow of the Tomb Raider benchmark: 44 FPS

At 60 Hz, UNIGINE Superposition benchmark: 5466 points
At 120 Hz, UNIGINE Superposition benchmark: 5362 points

In KDE I checked that the performance is exactly the same regardless of the refresh rate.

How I tested this (Xfce 4.19 built from master on 2024-10-29):

1. Booted into runlevel 3 (terminal)
2. Ran rm ~/.config/xfce4/xfconf/xfce-perchannel-xml/* to reset settings to the default
3. Ran with startx
4. Disabled the compositor
5. Set the Adwaita-dark theme
6. Set the Elementary icon theme

Then I ran both benchmarks twice to ensure the caches wouldn't affect the results (spoiler: the results are basically the same).

Finally, I changed the refresh rate to 120 Hz and ran the benchmarks twice again. The results are in the beginning of this post.

System: AMD Ryzen 7840HS + GPU AMD 780M + 32 GB DDR5 + Samsung 980 M.2 NVMe
Distro: PorteuX 1.7 x64 current

P.S.: this doesn't seem to be a regression because I also tested on Xfce 4.18 and the results are the same.