MacBook Air CPU core PECI temperature I have a question about my MacBook Air CPU temperature. I've read a lot of similar questions but there's something I can't understand in my experience. 

I'm doing some tests because I'm trying to figure out whether my computer would endure a live streaming of 12 hours (it's a school music project). When I run Wirecast the first time CPU core PECI temperature (which I monitor with iStat menus app) gets really high (80°-99°), then I get scared and I tried to stream at a lower video resolution and it seems it works... I mean, fan runs at a very low speed or doesn't run at all and the CPU (if I don't touch anything and leave the computer streaming only) gets a reasonable percentage of about 50%. But there's something strange... the temperature "CPU core PECI" it's still about 80°C-95°C! but if I open up the iStat menus menu the only red-written temperature is "camera proximity" with 64°C.

Does anyone of you know what's going on? Do you think it's dangerous for my computer to make this live streaming?
Here are some things to keep in mind for your streaming event. 


If the CPU gets too hot, the MacBook will throttle and reduce clock speed. That could result in dropped frames. Most of the time you will hardly notice the difference. 
iStat Menu has a utility to override fan speeds. In your case I would consider cranking up the fan to full speed during the streaming event, unless the noise is an issue. 
During the event put something underneath your MacBook so air can circulate below it. That doesn't do miracles but results in 1-2 degrees less and therefore less risk of throttling / dropped frames. 


Macs have pretty sophisticated cooling design and CPU temperature is not the only aspect taken into account for controlling fan speed. I would suggest you do another dry run for 2-3 hours. If you don't have issues during that time 12 hours should work as well.