So what does it mean when both my GPU and CPU are operating at ~25%? I’m not hitting the ceiling on any single core on my CPU during these moments. I don’t use VSync. I find that when this happens, it comes down to the server I’m on, and not so much my location within the server. This is when people across the PU usually start noting in chat that there is some FPS issues. The funny thing is, most people report around the same FPS with varying levels of hardware utilisation. If I switch computers, it’s the same thing. There is almost the same FPS with increased hardware utilisation (weaker hardware specs on the second computer).
This would obviously be guesswork, but I’d guess that there’s some piece of CPU work that everything’s having to wait for. I can’t explain why that wouldn’t show up as a maxed-out core, but it may be that the work is migrating from core to core, or that it’s a critical path of dependent tasks that are having to wait for one another? We do have a telemetry system that we use internally for capturing these kinds of situations though, which can be helpful as they just visualise all the different tasks as long green bars with names on them, and we can scroll around and see what’s causing gaps where.