If it reboots "almost straight away" then I think it's unlikely to be thermals. My first thought would be PSU.
And, yes, anything that causes your machine to reboot unexpectedly needs fixing even if it only happens under certain circumstances as you never know when you'll hit that in real life.
And, yes, anything that causes your machine to reboot unexpectedly needs fixing even if it only happens under certain circumstances as you never know when you'll hit that in real life.


