Question Why doesn't my laptop shut down when the CPU gets too hot ?

[Clay201]

I have a Dell Latitude E5570 Laptop with an I7-6820HQ processor, 16GB of RAM, an NVMe drive, and an AMD Radeon R7 M370 (2GB) GPU. It runs Windows 10. I bought it second-hand last year and cleaned it thoroughly, inside and out, after I got it home. The laptop gets used infrequently and when it is, it's just for writing, basic web browsing, maybe a bit of Youtube here and there. For anything that requires heavy lifting, I have a desktop.

Whenever I do use the laptop, I find that its bottom gets alarmingly warm, the side vents pump out very hot air, and even the keyboard and wrist-rest get very warm. I've used plenty of laptops in my day and I don't remember any of them getting this hot externally.

I installed a utility called HWInfo so I could check on the internal temperatures. It reports CPU temps between 110 and 125 F when the machine is idle (1-3% CPU utilization).

To test how it performs under load, I opened the Firefox browser, found a 4K, 30fps Youtube video and let it play, resulting in 45-50% CPU utilization. Under these conditions, HWInfo reports CPU temps fluctuating between 175 and 190. When I switched to a 4K, 60fps video, CPU utilization increased to 75% or so and temperatures soon climbed as high as 208. At that point, the numbers turned red, so I closed the browser. Temps dropped back down to 130-145 and utilization dropped as well.

I discovered that the system was using the onboard graphics processor and ignoring the Radeon R7, so I disabled the onboard graphics in the device manager. The system began using the Radeon R7 instead, but it resulted in no change to the internal or the external temps.

In the UEFI (or BIOS, if you prefer) I disabled an option identified as "Intel SpeedStep" but this also failed to change anything.

I'm sure I'll end up removing the CPU heatsink, checking everything out as best I can, cleaning whatever there is to clean, then applying some fresh thermal paste and putting everything back where it belongs. But before I do that, I need to know...

1. Why didn't my computer shut down when the CPU temps reached 208? I've had computers overheat before and they always shut themselves down (or at least rebooted) when they got too hot. Is this feature malfunctioning on my laptop? And if it is, how do I fix it?

2. Why is there so much external heat even when the CPU temps are within normal range? This isn't normal. What's going on?

3. What is a normal temperature range for my CPU? Google says that anything north of about 190 is too high. HWInfo seems to think it can go up to about 200. What's the limit? And where should my numbers be when CPU utilization is at, say, 50%? How about 75%?

 

[Lutfij]

It reports CPU temps between 110 and 125 F when the machine is idle (1-3% CPU utilization).
If the F wasn't placed there by accident, then it's 37.8 Deg C and 51.6 Deg C, respectively. That's fine.

To test how it performs under load, I opened the Firefox browser, found a 4K, 30fps Youtube video and let it play, resulting in 45-50% CPU utilization. Under these conditions, HWInfo reports CPU temps fluctuating between 175 and 190. When I switched to a 4K, 60fps video, CPU utilization increased to 75% or so and temperatures soon climbed as high as 208.
https://www.dell.com/support/manual...36cfd7-e9b0-4602-885c-54d3c4579ba2&lang=en-us
4K on a laptop that ultimately output 1080p on your display is an unrealistic test to subject the laptop under.

208 Deg F is 98.3 Deg C
https://www.intel.com/content/www/u...r-8m-cache-up-to-3-60-ghz/specifications.html
below 100 Deg C as stated in TJunction.

If you're concerned about temps, I'd advise using ThrottleStop and undervotling the CPU vcore, cache, iGPU and then the discrete GPU.

 

[Clay201]

Thanks for the reply.

208 Deg F is 98.3 Deg C
https://www.intel.com/content/www/u...r-8m-cache-up-to-3-60-ghz/specifications.html
below 100 Deg C as stated in TJunction.

Thank you. This solves one mystery. The laptop didn't shut down because it didn't quite reach the upper temp limit. However, I'm still alarmed that it came so close to the limit while the CPU utilization only reached 75%. This certainly sounds to me like the CPU is running hotter than it should. What do you think?

(Presumably, the fix will still be some cleaning and some new thermal paste. I just want to make sure I understand what's going on.)

 

[JayGau]

Thanks for the reply.


Thank you. This solves one mystery. The laptop didn't shut down because it didn't quite reach the upper temp limit. However, I'm still alarmed that it came so close to the limit while the CPU utilization only reached 75%. This certainly sounds to me like the CPU is running hotter than it should. What do you think?

(Presumably, the fix will still be some cleaning and some new thermal paste. I just want to make sure I understand what's going on.)

What's surprising is that the CPU is loaded at 75% while only watching youtube. But it's an old CPU with only 4 cores so it might not take very much to load it. And laptop thermals are also not always great. With this CPU I assume it's an old computer. You could try to open it and blow out the dust from the fans, heatsinks and vents. If there is some piled dirt or dust inside that prevents the heat to get out, the CPU and the latop itself will get hot.

 

[Clay201]

What's surprising is that the CPU is loaded at 75% while only watching youtube. But it's an old CPU with only 4 cores so it might not take very much to load it. And laptop thermals are also not always great. With this CPU I assume it's an old computer. You could try to open it and blow out the dust from the fans, heatsinks and vents. If there is some piled dirt or dust inside that prevents the heat to get out, the CPU and the latop itself will get hot.

As I said in my original post, It's very clean, both inside and out. I suppose there could be dust and gunk hiding underneath the heatsink. I haven't taken that off yet and I don't know how much room there is under there.

But regarding the temperature, I'm a little confused... Are you saying that a CPU temp of 98.3 C is not unusual when it's at 75% utilization?

 

[Misgar]

Are you saying that a CPU temp of 98.3 C is not unusual when it's at 75% utilization?

It depends on several things:

What was the ambient temperature of the room where you were using the laptop? If, for sake of argument, it was a sweltering 104°F (+40°C), I wouldn't be surprised if the CPU peaked at 208°F (+98.3°C) at 75% load. Even at 71°F (+21°C) ambient room temperature, the laptop will still get warm.

Next, consider where the laptop is located. If it's sitting on top of a bed and the air intakes underneath are completely blocked, the cooling fan(s) won't be able to move air through the heatsink vanes.

If the fan bearings are failing or the blades don't spin up to maximum revolutions, cooling will be compromised.

If the laptop contains two fans, but one fan has stopped working, cooling may be inadequate.

CPU-World shows the i7-6820HQ has a nominal TDP rating of 45W. That's a considerable amount of heat to dissipate in a non-gaming laptop.
https://www.cpu-world.com/CPUs/Core_i7/Intel-Core i7-6820HQ Mobile processor.html

It's possible Dell may have tailored the profile of the i7-6820HQ so that it doesn't use all 45W, to increase battery life. As an example of the heat being produced, you wouldn't hold a 40W Tungsten light bulb in your hand very long when illuminated.

Many laptop heatsinks are a compromise because space and weight are at a premium. If a desktop PC has a powerful CPU, you can fit a huge dual tower heatsink or triple fan AIO. As a result, laptops designed for portability might not always have the best cooling possible.

Presumably, the fix will still be some cleaning and some new thermal paste.

I've repasted hundreds of desktop CPUs, but never touched a laptop. I'm wary of possible difficulties if the laptop manufacturer used thermally conductive epoxy resin glue, as opposed to standard Silicone oil-based thermal paste.
https://www.masterbond.com/properties/thermally-conductive-epoxy-adhesives

Removing a laptop heatsink could be tricky when glued down. If the heatsink refuses to budge, don't apply brute force and potentially damage the Silicon die. Check out a few repair videos for your particular laptop before proceeding.

If your laptop doesn't shut down when the CPU is near the boiling point of water, the cooling system is maintaining temperatures within the "thermal design envelope".

I'd leave off repasting the CPU unless the laptop crashes repeatedly under load and accept that a 45W processor will get toasty warm at times.