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Pi 3 overheating

Posted: Wed May 24, 2017 4:54 pm
by dirthurts
Hi there,

As stated in the topic, my Raspberry pi 3 is overheating. It's hitting 80C and throttling really hard. I'm using the Raspberry Pi Foundation case, which I assumed was fine, but I'm thinking that's the problem.

I have some heatsinks on the way, but they're from China and taking forever.

I was always told that the Pi 3 didn't need heatsinks, and it baffles me to think that the Foundation case might be bad for them. Any other thoughts?

It's worth noting that I was just running a youtube clip when it happened (rather quickly).

Re: Pi 3 overheating

Posted: Wed May 24, 2017 5:30 pm
by mahjongg
It has always been said that a PI3 needs a heatsink on the SoC if you start using the GPU intensively (as in decoding video), or it will throttle down do avoid becoming too hot.

Re: Pi 3 overheating

Posted: Wed May 24, 2017 5:38 pm
by dirthurts
Hmmm.
I never considered that watching Youtube is actually decoding. I guess I'll have to get a heatsink on this thing faster.
Think I'll need to replace the case? There appears to be no vents on it.

Re: Pi 3 overheating

Posted: Wed May 24, 2017 5:54 pm
by fred44nl
how can you tell that the processor is throttling down ??

Re: Pi 3 overheating

Posted: Wed May 24, 2017 6:02 pm
by dirthurts
Everything gets stuttery and practically freezes as it hits 80c. It's a dramatic change. Temperature tested via terminal commands, confirmed by not being able to touch the CPU without literally hurting myself (it got that hot).
Plus, a blood red thermometer shows up in the upper right hand side of the display.

Re: Pi 3 overheating

Posted: Wed May 24, 2017 6:25 pm
by jahboater
fred44nl wrote:how can you tell that the processor is throttling down ??
https://github.com/MilhouseVH/bcmstat/b ... bcmstat.sh
Run this and you can see the temps/clock speeds in real time.

Re: Pi 3 overheating

Posted: Wed May 24, 2017 6:45 pm
by dirthurts
I have the program running above, but it's very complicated to look at and hard to read. But, it works. I'm idling iwth the case top off at around 55-57 C.
That can't be normal. Is my unit defective in some way? My other Pi 3 doesn't have this issue at all.

Re: Pi 3 overheating

Posted: Thu May 25, 2017 9:22 am
by jamesh
It sounds like you are doing software decoding rather than using the HW decoder. SW decoding video will run all four ARM cores at full tilt, which is where the heat is coming from.

If you can use HW decoding, you should. Keeps things a lot cooler.

Re: Pi 3 overheating

Posted: Thu May 25, 2017 9:44 am
by startrek.steve
fred44nl wrote:how can you tell that the processor is throttling down ??
I can see it in Conky, very useful.

Steve

Re: Pi 3 overheating

Posted: Thu May 25, 2017 11:50 am
by dirthurts
How can I use hardware decoding on Youtube?
I'm quite new to this stuff. Still trying to figure out Python...

Re: Pi 3 overheating

Posted: Thu May 25, 2017 5:52 pm
by fred44nl
startrek.steve wrote:
fred44nl wrote:how can you tell that the processor is throttling down ??
I can see it in Conky, very useful.
is there also a command-line option ??

Re: Pi 3 overheating

Posted: Thu May 25, 2017 11:20 pm
by dirthurts
Just an update.
I ordered another Pi 3 and popped in the same SD card (and thus installation) and it idles 15 degrees C cooler and runs much cooler under load with only a little throttling under heavy work loads. There's definitely something up, or these things are just made with no consistency to them. I'm going to drop a heat sink on the original and see if that helps.