S2-cpu overheating when rooted,temp fine with stock kernel topic

Hi guys,haven't been here for a while.7 months in a roll I had overheating problem.Underclock/undervolt-no change.One day I had to flash a new rom,but I forgot to root it.After short time of use I figured that it actually doesn't heat up...That's a new one for me.With stock kernel everything is ok.My prob. Is that i need my device to be rooted and i don't wanna touch hot cpu.Can you think of an advice?Thanks in advance :)

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