Originally posted by umop-apisdn:

Is it a thermal issue, or something else?

Have you contacted the manufacturer's technical support? This sounds like a problem with your equipment, which this unoptimized early-access title is somehow bringing to light, rather than it being somehow the Valheim developers' fault that your notebook is acting up.

if it was a thermal issue then my laptop would melt when playing Metro Exodus or RDR2.