Originally posted by umop-apisdn:

Yes, obviously the Windows update causing incorrect GPU switching is what causes the OP's issue in one specific area of the game world and not anywhere else. /s

The fact of the matter is that "excessive" terraforming and building in a relatively small region destroys framerates... and has for years. Again, this is a known issue. It's caused by the fact that the terrain is randomly generated, so instead of being able to update "the map", changes to terrain (and building pieces themselves) are saved individually; when a certain critical threshold is reached (which is somewhat hardware dependent, the game does more loading than rendering, which means the frame time increases, which means fewer frames per second.

Since you obviously didn't read the first thread I linked, here's another one from the same time frame, but on reddit. Maybe you'll believe the gamer nerds, since you won't believe the gamer geeks? This is not wild conjecture; this has been tested (repeatedly) and proven.
https://www.reddit.com/r/valheim/comments/m3sq72/instances_data_and_fpsefficient_base_building/

if you don't understand how ONLY USING THE CPU can cause the game to lag in FPS when coming near massive builds then you don't have any business commenting on the thread.

like i said, i had the SAME issues before i fixed the problem.

to clarify people, YOU ARE RUNNING THE GAME USING ONLY YOUR CPU, WHICH MEANS IT MAY RUN FINE WHEN OUT IN THE OPEN WITHOUT MASSIVE BUILDINGS, BUT ONCE IT COMES TO RENDERING IN BASE PIECES THE GAME WILL BOG DOWN BECAUSE AS I'VE SAID MULTIPLE TIMES NOW:

YOU ARE NOT USING YOUR GPU TO PLAY THE GAME.

before changing the setting in the graphics menu:

0% GPU usage, 100% CPU usage on task manager.

after changing the dedicated gpu from "auto" to High performance NVIDIA GPU, it now actually uses around 30% of my gpu and 30% of my cpu, and runs GREAT at around 99 fps when in a massive village.

seriously guys, there's a fix, i've told you how to do it.

there's no reason to come at me and say i don't know what im talking about when I'VE LITERALLY FIXED THIS ISSUE ON MY END.