Comment by Animats

In big-world high-detail games, the rendering operation wants so much time that the main thread has time for little else. There's physics, there's networking, there's game movement, there's NPC AI - those all need some time. If you can get that time from another CPU, rendering tends to go faster.

I tend to overdo parallelism. Load this file into a Tracy profile, version 0.10.0, and you can see what all the threads in my program are doing.[1] Currently I'm dealing with locking stalls at the WGPU level. If you have application/Rend3/WGPU/Vulkan/GPU parallism, every layer has to get it right.

Why? Because the C++ clients hit a framerate wall, with the main thread at 100% and no way to get faster.

[1] https://animats.com/sl/misc/traces/clockhavenspeed02.tracy