This one is rendered on my dual Xeon E5-2680 machine at 4K resolution.

Ray tracing seemed to have an almost perfectly linear scaling, since this took me 34 seconds on this machine with 16 total cores across two processor chips, but a similar ray tracing took me almost two minutes on a quad-core machine with slightly faster cores.
I wonder if KiCad have a render to file option? That might be useful if I want to produce a printout for my projects, I can render extra high resolution images (for example, 15320x8640 or 16K 8640p - 16x pixels of the current 4K monitor.) Also since there would be more pixels to draw it also serves as a better benchmark.