Low GPU and CPU Usage: Slowly Decreases From 100 FPS to 2 FPS for 10 Minutes

[Jaffa Cakes]

I am having a very frustrating issue where, when there is a lot of activity on the map, my framerate drops to slideshow levels and becomes completely unplayable. This only happens periodically; it will gradually get laggier until I have around 2-3 fps, and then, after another 10 minutes, it will instantly go back to normal (around 110 fps) without anything changing in-game (there will still be 100 players, vehicles, and so on).

The interesting part about this issue is that my CPU and GPU usage are around 20%-35% utilized, with lower utilization rates the laggier the game gets. When the game is not laggy, my GPU usage reaches up to 100%, as expected.

Relevant parts of my rig include a Ryzen 5950x CPU, Radeon 7900XTX GPU, 4K 144Hz monitor, and a Gen 4 1TB NVMe. My computer is high spec, and I am a software engineer, so I believe there are no other programs or bottlenecks that should be causing this issue based on my experience. The system is not overheating and this problem does not occur in other games.

There are other people on the internet experiencing the same thing; I've tried several solutions mentioned in these threads with no improvement:
- https://www.reddit.com/r/HellLetLoose/comments/zwjezk/low_gpu_usage_still/
- https://steamcommunity.com/app/686810/discussions/1/3166519278502394575/?l=japanese
- https://forums.tomshardware.com/threads/rtx-3070-only-using-45-power-on-hell-let-loose-anyone-know-any-solves.3808917/
- https://steamcommunity.com/app/686810/discussions/0/7221028806369717412/

I will also note that reducing the graphics settings to low, and even down to 1080p instead of the 4K that my monitor supports, yields no improvements. After reviewing individual core usage on my CPU, it also seems that no cores are being maxed out.

This has been very annoying for me, as it causes 10-20 minute periods of unplayability roughly once or twice per game (sometimes not at all).

DxDiag information is available here: https://pastebin.com/W4UF53XA

Any help would be greatly appreciated.