Regular and high frametime spikes on mac

By observing the fast timers console, i noticed big regular frametime spikes (those frames have a double duration compared to other frames approximately).

The spikes happen with a shorter period when reflection coverage is set to manual vs none (with the option set to none, this is the sim general probe that is updated, so it happens less often).

This doesn't happen on Windows, or Linux.

I joined a couple screenshots, one with reflection coverage set to none, one set to manual only.

note 1: the frametime in ms indicated in the fast timers window isn't correct on macs with Apple silicon. But it's not very important here, what matters is the shape of the frames over time.

note 2: you might notice my disk cache is set to a low value. This is intended, and has no impact in this current test.

https://secondlife.canny.io/admin/board/bug-reports/p/regular-and-high-frametime-spikes-on-mac

Start by reproducing the issue on a Mac with Apple silicon using the fast timers console, comparing reflection coverage set to none and manual. Done means identifying the cause of the regular frametime spikes and confirming that the spike pattern is corrected on macOS without regressing Windows or Linux behavior.