Originally posted by Max:

I'm use 5700xt + r7 3700x + 16gb ram, I play on low setting. And yes mostly is lag bc I play with my two friend (they have low spec pc so they fps is even worst), but when I'm Offline got boost by 10-15fps+ so the gameplay like 25-35fps.

Could it be a problem with AMD/Radeon systems? Your system should be quiet similar to mine. Maybe 10-20 FPS lower, but you wrote about constant 10-15 FPS prior.

Someone from our group got a GeForce 3090 RTX with AMD Ryzen 7 5800 and has a lot more FPS than me. He always plays with 100+ even in mainbase with all entitys. At least it doesn't drop below 70 for me / even in the worst situations. Mostly I play 100-144 FPS while exploring. Mistlands maybe 10 FPS less compared, because of the mist.

Try to configure your boot.ini (just google-you'll find) / set priority in task manager to "high", deactivate steam overlay, start the game in "window mode fullscreen", etc.