EDIT Seems that valve fixed this problem???
I'm referring to the 4/3/24 cs2 update

Let's start

Parallel processing is used everywhere:
- Particles
- Animations
- Client-side Prediction
- Network processing

EDIT 3/31/2024:
If your game is running fine or you are running lower end processor this "fix" must be pointless for you.
There is no magic behind this "fix" and there are a lot of other factors that can impact the perfomance.
RAM and it's frequency, CPU and it's frequency, system itself, let's continue on topic...

So "-threads N" means that game will create N-1 additional threads for parallel processing. This all depends on your real P-Core count.
Before you continue, I recommend you to double check information about your processor on ark.intel or any respected source.

I.E
Add launch option "-threads N" where N is an ammount of needed cores.
We have tested ("-thread 8" and "-threads 9").
Why exactly these values for i9-13900K and i9-13900KS?
You can follow this link to get some more overview (https://www.techpowerup.com/cpu-specs/core-i9-13900k.c2817)
Here you will see smth like this:
P-Cores: 8

And why second variant was 9?
By referencing what was stated above
Quote: "So "-threads N" means that game will create N-1 additional threads for parallel processing"

This "fix" was heavily tested on i9-13900K and i9-13900KS respectable it gave a huge impovement in game frametime stability and
in-game "net_graph" almost never shows any stuttering at all.
Check it with "sys_info" convar to ensure on how much threads game is actually running.

I've also tested https://github.com/GameTechDev/HybridDetect on main game threads, it seemed to make the situation worse.
Also changing processor affinity on cs2.exe seems to be a total waste of time.
Disabling E-Cores adds rubberbanding to anything in cs2.

12-14th Intel Gen is a total meme, thanks Intel also Valve should test their games on popular hardware sometimes...