Download is free on Steam. It just uses the shareware version of Quake II.
To launch the benchmark press tilde (~) then enter the following
timedemo 1
demo demo1
Can be used for comparing OpenGL to RTX
For reference my 2080Ti does the following
RTX high global illumination
3440x1440 - 42.7fps
1080p - 97 fps
720p - 190fps
Open GL high settings
3440x1440 - 1867fps
1080p - 1903fps
Granted the lower settings will be much higher fps on a machine with a newer CPU than mine but it doesnt bother me I can't play games in Open GL at 2000fps in 1080p
For testing how well current hardware handles global illumination, path tracing etc. though, its very good. It does actually make a huge different to the game atmosphere (once you lower the default brightless)
Quake II is gritty and looks fantastic with RTX hardware - it's not support to be super bright though