Follow-up to my last post, my friend uses a Windows laptop - AMD Ryzen 9 with a NVIDIA GeForce RTX 3070 - and we compared frame rates to my MBP 14" (M1 Max 10/32/32 32G RAM) with same settings in a number of enviros. Overall I'm getting about 70-80% the frame rate on the MBP compared to that. It isn't that fastest Windows laptop in the world but reasonably fast, and the Mac is running FS with Rosetta. The rendering code has always been more optimized for Windows anyway.
I'm guessing the reason my Mac never heats up is that the renderer is single threaded. So it maxes out one thread and can never distribute the load to other processors enough to take advantage of speed increase and produce heat.
It's unlikely that the Mac world will ever see a native renderer written in Metal due to the amount of work required, however I'm hopeful something will be done using Vulkan, which could potentially be a lot less work.
@RaffaeloMonastir - the "Open using Rosetta" option is only present for apps that have both ARM and x86 code (universal binary) -The Mac will default to the faster ARM option unless you check that box. This is not the case for Firestorm or any of the viewers, they only have x86 code, so they launch automatically with Rosetta2 or they don't run at all, and they don't include that checkbox.
Regarding Windows emulators, I've read that Parallels works quite well, and is currently the only Windows platform that runs on Apple Silicon. I don't think this is relevant though to SL or Opensim.