4Game

Foreword:
(my specs: GTX 1060 6gb, 16gb RAM 2666MHz, Ryzen 1700X, windows and game installed on SSD.)
I started playing 12.12 patch about week ago. My last patch was 12.10, I don't remember, but the fact that I haven't played Tarkov for a very long time. All was fine previous patches, in low-med settings, but with some tweaks I was able to play without stutters and with strong FPS around 75-80 on customs, interchange etc.
Nowadays I was shocked and scared that my PC really needs technical care. I cleaned my PC, replaced thermal paste on CPU, optimized windows and did many, many other things that everyone do but I not.
After all those steps I decided to check how EFT will react to all these changes. I was surprised by 110-130 FPS in offline without bots. "Wow, my potato can still handle my favorite Tarkov!" – I thought.
Tested on woods, interchange, reserve and many other maps – same FPS counter.
Tried play offline with bots – same FPS counter, but with long stutters when bots spawns.
Ok, let's try this in online raid! Then I was re-shocked by FPS counter about 58-60 and a lot of micro-freezes, I would even say "nano-freezes", but those freezes were so annoying, that I was killed after I met first PMC.

The Main Idea:
I was testing Tarkov all this day. I tried low settings, high settings, a lot of optimization guides… But after one moment I just realized one thing.
When I was playing offline, my gpu was loaded by 90-95%. I had a lot of FPS and I was really happy!
But in online raid, my gpu load was reduced to 30-35%. WTF? Again 55 FPS? Really? What happening?
I can't really explain what's happening behind the Tarkov's code. Maybe it's BattleEye, that's loads system AF, maybe it's bots and players, that for really strange reason start eating CPU really hard. Maybe something else, idk.

And you know what helps me?
This guide guys: Possible Low Gpu Utilization fix (Nvidia) : EscapefromTarkov (reddit.com)
Also I changed textures on high and shadows on ultra. Now I have strong 80-85 FPS without nano-stutters and my GPU loaded by 70-80%.

That's all.