[Atrix 4G Q&A, Help & Troubleshooting] sathelate:
Yeah he is right and this is normal behavior! On PC we have fans and CPU sync to pull the heat away! In our phone tho, what are we having? Nothing!

so yeah he is not lying! My phone stays between 50C and 60C while playing accelerated 2D games and climb to 65C, sometimes even 70C

So now, try to imagine that without an active source of ventilation, EVERY part producing heat.

Try this : use utorrent for a download over the 3G data of your phone, while at the same time stream video for about 10 minutes, then just after it, start the GPS tracking on your way on feet to your park for an exemple, then, start playing a 3D game!

what will occurs : Got mine on a 1ghz stock kernel running at 84C !

The phone is set so that when the CPU touch high temperature, it shut itself to prevent further damage!

Now that i have an OC kernel, i'be had once got it to 98C just on tracking GPS in the car facing the sun behind the windshield ... well, I've forgot to downclocked and the phone became really hot and became unstable and really laggy! Trying to pull TTS service was incomprehensible until the phone get stuck ... then i realised, but starting the AC in the car defrost mode to have fresh air over the phone was too late ... so the phone shut itself completely! Was unable to power it on!

I was scared but i remembered then that this is built to avoid the CPU get damaged ... so i waited a bit for the heat to get out s bit, then it powered on no problem, it was back to 62C

Morality : It is actually scary to see those kind of temperature, but this become normal over time if you are an heavy user : i mean :the galaxy S3 of my friends is idling at 29C and when in use, at 55C .... when gaming : 75C ... so this is not just our phone ...

Its the dual core madness without having an active cooling system

I'm not saying that over time i can't get damaged with those kind of heat on a long time basis but i got my atrix in February 2012 and from that time, I've became addict to my phone (my.fphone is actualy faster than my old pc hahaha) and can use it like 4 hours per evenning and easely 2hours on screen on during the day in my breaks! Also my job require me to be on the phone often

And I've never had problem with my phone ;)

First thing : Motorola temp sensor is hard to reach, there only a few app on the store that can actually read the CPU temp while the bat temp is super easy to access!

Tempmonitor from the store can read your CPU temp

So, 37 degrees is your battery temperature even if the program telling you that you are actually reading CPU temp ... well .. its FAKE because as soon as you turn on your screen, the CPU temp start climbing from 25 to 28C to 55C in about 50 seconds! It is actually normal!

Last thing : To the OP : as stated before, your first objective is to see what app causing a stress load on the cpu using watchdog while the phone is sleeping inside your pocket because THIS is far from normal! The CPU clock when the phone hibernate is 45Mhz ... so not a damned reason is supposed to get high even in a rooted state! So, font worry, it m is not a bad things you did during the rooting process ... but certainly is a app that eat lots of CPU ressources that stoping it from hibernation state

If you find nothing abnormal, then, return it ASAP :D