Very low graphics using lot of performance

Hi, my friend told me he couldn't run my game on his computer because it was crashing and he was playing in very low quality. I tried to play it on a laptop with a good graphics card and it was very laggy even at very low (5 fps). When I run the game on my PC in very low, the game is using 25% of my GPU and 30% CPU! (I have a GTX 1080 Ti) but very high is using 60% GPU. I tried to make an HDRP preset for each quality, but it doesn't change a lot of things even if I remove some options. This is how the game looks like at very low. Any idea what it could be?

 

Unity has a profiler that analyzes your performance so you can see exactly what's happening:
https://docs.unity3d.com/Manual/Profiler.html

 

@Tornado77
Did you figure out what was causing it?

 

Yep, the number of terrains. I had at least 15 terrains with a mesh resolution of 4096x4096 in my scene.