Specs? Is it Clean? Hows your airflow? How old is your hardware (new thermal paste maybe)?
Try under clocking your GPU and drop your power limit a bit.

Originally posted by Djemed:

Originally posted by retrorhett88:

dust always builds up everywhere and can clog up the fan and vents so you should take an air hose and blow it all out. i do this for my cp and my playstion and i still have the first ps4 when they came out. you would be surprized how much less noise you pc will make.

Thing is my PC is clean and there is no dust or very little, just when i play this game my GPU temperature starts rising from 50C to 85C

When was the last time you replaced the thermal past on your CPU and GPU? If it hasn't been done since you bought/built your PC then its probably contributing to the heat issue.

This game badly optimized

your pc should be able to run full speed without getting hot. This is a hardware problem, not a game problem, the game may be taxing the system but it should be able to handle it. Check your fans, blow out the dust, reseal the CPU with new compound if its more than 2-3 years old. Make sure it has airflow. If that isn't cutting it, move the components around a bit can help: make sure the power supply is away from the graphics card, for example. A bigger case is not too expensive, or if you have room, take the power out of the case and sit it on top or to the side can give you better airflow and remove a major heat source.

Originally posted by Djemed:

When i play this game my GPU goes to 80 Celsius and more, CPU goes to 70 Celsius and it is only case with this game. Is there any fix to this ?

PC specs? No one can actually help or give advice unless you tell us what you have under the hood. :)

i play this on an 2nd gen i5 760gtx and ill use kinda high settings so all who complain about this just have bad cooling. even on max settings i reach 80c. sure its low fps when build to much but if not to much is changed on map like terrain and buildings then i have about 50-60fps. so if farm on other maps and have one map for homebase i never seen any issues. just upgrade ur coolingsystem.

Originally posted by Djemed:

Originally posted by retrorhett88:

dust always builds up everywhere and can clog up the fan and vents so you should take an air hose and blow it all out. i do this for my cp and my playstion and i still have the first ps4 when they came out. you would be surprized how much less noise you pc will make.

Thing is my PC is clean and there is no dust or very little, just when i play this game my GPU temperature starts rising from 50C to 85C

temperature means usage. Obviously, your hardware is being used hard, thus resulting in excessive heat being generated.
Valheim is NOT light on your system regardless of the seemed visual simplicity. In my opinion, the game was made "low quality" because its so taxing on your hardware. People who ask for "better visuals and more quality textures" just don't understand the consequences of their request.

Originally posted by retrorhett88:

dust always builds up everywhere and can clog up the fan and vents so you should take an air hose and blow it all out. i do this for my cp and my playstion and i still have the first ps4 when they came out. you would be surprized how much less noise you pc will make.

Thing is my PC is clean and there is no dust or very little, just when i play this game my GPU temperature starts rising from 50C to 85C

dust always builds up everywhere and can clog up the fan and vents so you should take an air hose and blow it all out. i do this for my cp and my playstion and i still have the first ps4 when they came out. you would be surprized how much less noise you pc will make.

Most likely causes are bad drivers, failing components or poor cooling. Never hurts to try a fresh install of drivers, but to do so properly you need to completely remove all files and settings using a tool like DDU, Display Driver Uninstaller in safe-mode.

Where do you play this game? PC or laptop?
I'm playing on the laptop and yes it makes my laptop hot my GPU around 70 and the CPU around 80 or even 90 sometimes when the ambient temp is hot.
I only play at night with AC on to makes it stable around 70 both GPU and CPU.

my cpu goes to 60 degrees under heavy load and my room temperature is 30 c°

Limit fps?

What is the Unity Engine like? First time I've really played a game with this engine.

Originally posted by Djemed:

Why is my PC Overheating ?
When i play this game my GPU goes to 80 Celsius and more, CPU goes to 70 Celsius and it is only case with this game. Is there any fix to this ?

Your PC is overheating?
My PC automatically shuts down when my CPU reaches 97 Celsius, which happens occasionally during the summer and the ambient temperature in my room is too hot.
My system is fan cooled and fans will not cool the CPU enough if the airflow is already heated.
Therefore, I restrict my game time to the cooler hours if at all during the warmest months of the year.