Is there a temperature sensor on Pine?

[Informatica]

Hi, 
I installed CPU-Z (android) for monitoring processor and memory and I noticed that in the "Thermal" tab, the application show a specific value of temperature (about 50°C). It grows up (about 54°C) after video playing.

So, is there a temperature sensor on Pine or it is a fake temperature?

[Keex]

Yes there is a temperature sensor in the CPU, so the temperature isn't fake. Maybe someone else can pitch in here with some more details.

[g_t_j]

It would be interesting if you post your temperatures here.

I get around 65 degrees running tinycam monitor (CPU-Z under thermal tab)

It is supposed the CPU to start throttling when the temperature reaches 80 degrees but in my case I have seen that when it gets 68-69 C, the board starts to decrease the clock speed.

The max clock speed I have seen is 1153Mhz

[pinea64.edison]

I have seen temperature going up to 72 C after watching videos in Kodi for about 1 hour. I have also noticed that the temperature does not go so high if i am using other apps to watch video. So I am wondering if there is any setting within Kodi (like hardware acceleration) which is the root cause for such a high temp.

Also do you know will these high temps cause damage to the board?

[g_t_j]

I have seen temperature going up to 72 C after watching videos in Kodi for about 1 hour. I have also noticed that the temperature does not go so high if i am using other apps to watch video. So I am wondering if there is any setting within Kodi (like hardware acceleration) which is the root cause for such a high temp.

Also do you know will these high temps cause damage to the board?

In my case, I have seen that deselecting HW acceleration in Kodi, gives me better performance.
I had problems streaming FHD material but after deselecting HW acceleration under Kodi settings, the results are noticeably better.

[Informatica]

Update:
Yesterday I used my Pine to do a temperature test.
I noticed that:
-the temperature in "thermal" tab is "30.0°C" and it doesn't change whatever I do.
-the temperature in "sensor" tab changes every second from 45 (just started up) up to 55°C (apparently it changes randomly).

Is it the same for you?

[g_t_j]

Update:
Yesterday I used my Pine to do a temperature test.
I noticed that:
-the temperature in "thermal" tab is "30.0°C" and it doesn't change whatever I do.
-the temperature in "sensor" tab changes every second from 45 (just started up) up to 55°C (apparently it change randomly).

Is it the same for you?

It's the same for me as well.
I suppose we disregard the thermal tab and just read what the sensor says.

I believe this is the normal range you mention, between 45 and 55 degrees C. It can climb over 70 degress when running demanding apps. 

I have found that heat sinks and cooling in general helps a lot with performance.

[Informatica]

I believe this is the normal range you mention, between 45 and 55 degrees C. It can climb over 70 degress when running demanding apps. 

I don't think that 45°C is normal for the board just started. It should be about 25-30°C (ambient temperature).

I have found that heat sinks and cooling in general helps a lot with performance.

Right!! I'm going to buy this (for raspberry but it is the same)
http://www.gearbest.com/development-boar...54470.html

[longsleep]

Using the Pine64 without heatsink gets you easily to to 45*C when running at full speed. This is perfectly normal and not a problem at all. The thermal configuration for the Linux images has been analyzed and optimized in detail (see https://github.com/longsleep/build-pine64-image/pull/3). Our settings for Linux have been adjusted to what we found and the board will start to throttle when reaching 80*C and can run perfectly fine at 95*C which is the maximum normally reachable with these optimized settings. The SoC will shut down at 108*C, and do heavy throttling with a multitude of steps only disabling cores as the last resort. All the details are easily visible in the device tree source (https://github.com/longsleep/build-pine6...2458-L2505).

Note that all these temperatures are the inner sensor value as reported by the SoC themal sensor. The chip is considerably cooler on the outside due to the plasic casing of the SoC.

A heatsink greatly improves heat dissipation for normal short burst work loads or in bad thermal environments (eg. inside a case with no air flow). Without a fan, the heat sink will reach its maximum dissipation capability after a couple of minutes of constant load (the exact time depends on the heat sink quality, ambient temperature and air flow).

I my testing, when with a heatsink and fan, it will give an average performance gain of 9%. Without a fan and a heat sink which maxes out at 50*C the average performance gain is around 3% (all under constant load, all cores).

To sum this up, without a fan it is impossible to keep below 80*C, with a good heatsink and fan the SoC temperature can stay at around 70*C at maximum speed heavy load (at 23*C ambient temperature).

---

One more thing not mentioned often enough. Doing any heavy load on the Pine64 will require a stable power supply which is almost impossible to get using micro USB powering. So if your board shuts of or freezes and you think it is the heat it most likely is not - you just got under voltage due to crappy power supply setup.

[pfeerick]

To sum this up, without a fan it is impossible to keep below 80*C, with a good heatsink and fan the SoC temperature can stay at around 70*C at maximum speed heavy load (at 23*C ambient temperature).

---

One more thing not mentioned often enough. Doing any heavy load on the Pine64 will require a stable power supply which is almost impossible to get using micro USB powering. So if your board shuts of or freezes and you think it is the heat it most likely is not - you just got under voltage due to crappy power supply setup.

I'd just like to add that it is quite informative watching your pine64_health.sh running (with the -w) flag when the pine64 is under load... ran stress on mine for several minutes flogging all the CPU cores, disk and memory I/O, and was able to see the CPU throttling to keep the core temp below 90*C (at 26*C ambient atm). 

Also, it is more often the MicroUSB lead that is the culprit, more often than the power supply (in my experience anyway... then again, I use 2.4A and 5A/10A rated PSUs, some tweaked to 5.2v  ). I have a load of microUSB cables that are either charge only (so no data wires, which is handy when you want to plug your phone in to get a file of it...) or just plain pathetic, they are useless for anything over 1A load (which is probably being too generous... more like 500ma). There is too much resistance in the wire & connector leading to warm cabling and voltage sag, and an unhappy pine64 if it gets loaded up. 

Hm... I wonder how well you could overclock the pine64 it it were installed in a fridge... internet connected fridge anyone?