This is not really a bug report, but more of an observation. I noticed the Mac viewer sees the framerate commonly divided by about 3 when activating shadows (sun/moon), for instance from 75 to 25, while a PC with an AMD integrated gpu, with the same settings and at the same place sees a more reasonable drop from 65 to 40 fps.

Its worth noting that the amd igpu utilisation is always maxed out (it's about twice weaker compared to the M2 Pro gpu), shadows on or off, while the Mac gpu sees its gpu utilization dropping significantly when activating shadows, indicating that shadows are limiting its efficiency in some way.

The cause can be driver related of course, but i thought i would leave this observation in case you find a way to optimise this.

Also i don't think this is due to "foreverfps", it must have been something going on for some time, but i really noticed this only today.

I also noticed this on a 3rd party arm compiled viewer, so this is not a Rosetta translation issue.