Last weekend, my newer pc, had a glitch, fixed now, so I tried running it on my 7 year old system, which is just above min spec with the gpu, gtx980m, has a quad core, and to my surprise, Valheim ran well, with some settings reduced, like shadows etc, and some effects turned off. That said, it was in the early game, so no building projects or terra forming, or large in game storage.

By comparison, my newer system is an 8 core, and while the gpu, rtx2080, runs fine, 4 cores get busy, with most settings on high. Tbf, the cpu needs thermal pasting, and is a bit overdue.

I'm awaiting delivery of some liquid metal paste, and keeping sliders in the middle, in game graphic settings, to try to keep the temperature in the sweet spot, for now.

In time the game will get optimised, until then, no shame in reducing settings, or tweaking your game and or system accordingly, at least from my limited experience, it is very playable, as it is.

VIP854, on paper you should be doing better than me, with a 2080 Super, I'm sure you know about CPUID Hardware monitor, or similar, have you checked your cpu temps / utilization while in game?