Computer basically idle, but poor performance?

[Issus]

I've read through all the guides for improving FPS/performance, but it seems my performance is about the same or worse as people were getting in 2013 with 2nd gen i7s and 600 series GTX cards.

I have a
* Ryzen Threadripper 3960X (24 core, most basic 3rd gen threadripper) - Overclocked 4.65GHz
* MSI TRX40 Creator motherboard
* 128GB 3600MHz CL18 RAM
* RTX 2080 Ti (overclocked)
* Samsung Evo 980 PCIE 4.0 NVMe SSD, (7gb/s read/write).

My main screen resolution is 3840x1600 (Dell Ultrasharp U3818).
It's an engineering/4k raw (like from cinema cameras) video editing computer, so its not too much of a slouch on performance.

I set my render size to 88%, because on the graphics menu anything above that drops me below the 320fps cap... ingame is a different story.

I play pretty much exclusively on 77th JSOC Coop servers, it doesnt matter if there are 15 or 60 players on - in base perhaps 30-40fps. In basic combat I'll have max 30fps. Heavy combat (defend HQ mission) its 23-25fps on Tanoa. Just walking through the jungle in tanoa is 23-25fps.

During all this, CPU is at 3-5% usage.
GPU is maxing out at 40-50% usage. I'm at 10.6GB of vram usage with high quality textures.

CPU fan is off, GPU fans are off. System is not stressed. I see higher resource usage just having Chrome and my 60% tabs open but not used.

I have Arma configured to use all the vram and system ram it wants, manually set to 24core, hyperthreading on, intel ram allocation, etc. Can't get the game to bring the system above idle.

Is there any more optimisation I can do? I pretty much only play as a medic, so FPS doesn't affect me quite so much - but it does give me a headache after a bit watching this slide show.

Pretty disappointing seeing 8 year old threads with people having old hardware even for the time getting basically the same performance as I see.

[29/P4TCH3R]

Might be the mission that is reducing the FPS, as you can run Arma 3 60+ FPS with good, less scripted and less moded missions.
But yeah, the engine is old and I mean very old. I think you can't do anything more for optiomization, but you could reduce your ViewDistance, that might help.