System Shuts Down. UE 5.3.

For CPU cooling i use Noctua ND-D15. cooler and fans are running well with no issues and i also often clean my pc from dust being gathered.
I reapplied thermal paste 3 months ago with COOLERMASTER CryoFuze W/m.k= 12.6m.
I just now after your suggestion (an hour ago) i update my bios to the latest verions launched this month.
(not to brag, but i have decent experience with assembling pc and maintaing it or trouble shooting the hardware :slight_smile: ) but this issue with unreal is the first from me as i am fairly new to it.

I have been using core temp from a long time and the temperatures are stable every time i have checked when using unreal. i have attached SS of my current GPU and CPU temp reading for reference.

there is no lag unless i use a heavy scene like with the sample scene, electric drems environment, hillside sample, city sample, slay animaton.
with these scenes there were times when it use to shutdown but when i increased my ram from 32 - 128 the crash stopped for a while with 5.3 and now it crashes again with UE5.4.

there were times it used to crash when the system was idle (while UE was running in BG) or while i work on other tasks with unreal engine ruinning with an empty porject.

i will test the engine again, with the smple projects instaled and will update you on the status.

thank you guys for the help.