Performance Issues - CPU Frame Rendering Spikes

The game has been running perfectly since launch, but after one of the recent patches, I've started experiencing severe performance issues. The game performs well for the first 30 minutes or more, but then, seemingly at random, CPU frame rendering time jumps from around 11ms to 50-60ms every time I move around. This causes the game to feel unplayable due to stuttering and lag.

The only way to resolve the issue is to completely quit the game and restart it. Simply reloading a zone or changing maps does not fix the problem.

OS: Ubuntu Linux (Steam version of the game)
CPU: AMD Ryzen 9 5950X
GPU: Radeon RX 7900 XTX
RAM: 64 GB

The issue occurs randomly during gameplay, but is most noticeable during:
- Clearing dense enemy packs or at the end of a map.
- Boss fights in the campaign.
- Areas with heavy effects like sparks, gas clouds, or dense mobs.

This issue is new and has only started after a recent patch.

I have 370+ hours of playtime, and the performance was excellent most of this time, until this issue appeared.

In the screenshot you can see the in-game graph showing CPU spiking when the character is moving around. And the frames being just fine when the character just stands immobile.

The CPU graph is btop running in another window, showing that the rendering of the GPU was just fine, and then it starts dipping for some reason as-if it is not receiving enough stuff to do.

This seems to have been resolved after the recent server restart. Although instead there are new "issues" that appeared, such as disappearing monsters, and infrequent complete halts.

I've had horrific issues with this today. Just upgraded my CPU (Ryzen 3600 -> Ryzen 5700x3D) hoping to fix my CPU performance issues.

However, seems like it's worse now.

Windows 10
Ryzen 5700x3D
6700XT
32 GB ram