Strange thing with CPU temp

I was looking at my temps and I noticed that CPU ones never goes between "intermediate stages", but from 30C (idle) they go all the way up to 80-85C (as soon as I start a heavy task), the same happens in the other way, I stop the heavy task and in less than a second the temp fall back to 30C. Plus I tried to launch Prime95 and, while on screen i read 87C, the air that exit from laptop was not very hot, after some gaming instead, with the temp at 78C the air was extremely hot. This makes me think that the displayed temp is wrong, and maybe is based0 on CPU usage.

 

CPU temp's are based on cpu usage.

I don't see anything wrong with what you're describing - just a very efficient heat process from the cpu to the cooler.

The air takes a while to heat up - gaming is a much longer time frame than launching Prime95, so of course a seemingly cooler temp will feel much warmer to your skin.

Does your system throttle or exhibit other unwanted behavior? If not, this seems par for the course.

 

Oh, thank you very much, at the end was all in my mind .

 

It shouldn't drop down from 87C to 30C in less than a second. There is no cooler that efficient. Matter of physics, it will take some time to cool down. Does seem odd. If there's any way you can run a quick video. FRAPS, or MSI Afterburner, Nvidia ShadowPlay or CamStudio (my pick) to do a quick video and upload to YouTube or other favorite video site.

The reason games probably feel hot and Prime95 doesn't is because Prime95 only taxes your CPU where a game will tax both your CPU and GPU. Although I would check CPU performance with Prime95 because sometimes systems blacklist apps like that and downclock significantly because it can unnecessarily overheat your CPU.

Here's mine with i7-4720HQ:

 

I didn't take it to be literally <1sec. Also, launching Prime95 is different than actually running it, no?

 

I guess it depends on how literal you take OP's comments, which is why I asked for a video.

 

Right now I'm not on the pc, anyway I meant one second literally. Talking about clock, it was fine (3 Ghz stable, until the temp reach 85 and then decrease to 2.7).

Oh with "launching Prime95" I meant "let it run for a couple of minutes".

 

I tried to do a video, but looks like every program i tried doesn't record the updates on temps, anyway i watched your video and your temps decrease over time, while mine don't. It doesn't bother me too much, but i have to be sure that max temps are real.

 

Some monitoring programs allow you to save a text log file of the temps recorded. You could set the program to take a log file when you game and then plot the temp vs time using Excel for example, then you'd get an idea of how fast temperatures fluctuate.

 

@Jajo240 Use Trottlestop that allow you to save a text log file of the temps and multi recorded.

 

Thanks guys for the hint, i used Throttlestop and got these results.

As you can see, the temp reach 90+C when i start Prime95, when i stop it, in 1 second decrease from 89C to 52C

 

Yeah, looks normal to me. You're only running Prime95 for a few seconds, after all...

 

Run the test much longer than half a minute. It is too short a time for the Heat Sink to warm up with such a short load..

 

Think about the heat output of a 60 Watt light bulb and now concentrate that energy into something the size of your pinky fingernail. The peak core temperature that software reports is coming from a tiny microscopic sized sensor, less than the size of a pin point on your finger nail. The instant you start Prime95 your CPU goes to full power and it immediately gets extremely hot. The moment Prime95 is stopped, the opposite happens and your CPU cools down just as quickly.

A long, long time ago I could never believe that a CPU could get so hot. I thought someone might be confusing Celsius with Fahrenheit. The temperature sensors must be wrong so I pulled the heatsink off of my Pentium III and used the most accurate temperature monitoring device I had available. My thumb. After I pushed the power button, it wasn't long before I pulled my thumb off of the die.

The nice little mark on my thumb was all the convincing I needed. Lucky I pulled the plug before cooking the core.

 

I've never seen a CPU with a heat sink change temperature so quickly.

Is the heat sink properly thermally connected. The temperature change speeds are more appropriate to a CPU without a heat sink where the maximum temperature is controlled by automatic speed throtting to stop the chip from frying and there is only a small bit of silicon to cool down when the speed is reduced.

John

 

First, thanks to everyone for the help.

So, we have the "nothing strange team" winning 3-1 for now . Tomorrow I will try to let prime95 run for a longer time (how much? Is 5 minutes enough?) and then I will re-update the log.

 

Code:

   DATE       TIME    MULTI   C0%   CKMOD  CHIPM   BAT_mW  TEMP  GPU     VID   POWER
2015-07-14  18:46:41  35.08    4.1  100.0  100.0        0   48     0   1.0457    7.0
2015-07-14  18:46:42  35.03    5.0  100.0  100.0        0   49     0   1.0463    8.5
2015-07-14  18:46:43  35.02    0.7  100.0  100.0        0   47     0   1.0457    2.5
2015-07-14  18:46:44  29.90   79.7  100.0  100.0        0   82     0   0.9832   45.8
2015-07-14  18:46:45  29.28   99.5  100.0  100.0        0   85     0   0.9591   56.0
2015-07-14  18:46:46  29.24   99.6  100.0  100.0        0   86     0   0.9591   55.7
2015-07-14  18:46:47  29.17   99.7  100.0  100.0        0   87     0   0.9591   56.0
2015-07-14  18:46:48  29.19   99.6  100.0  100.0        0   88     0   0.9591   56.0
2015-07-14  18:46:49  29.16   99.7  100.0  100.0        0   88     0   0.9591   56.0
2015-07-14  18:46:50  29.19   99.6  100.0  100.0        0   90     0   0.9832   56.0
2015-07-14  18:46:51  29.17   99.7  100.0  100.0        0   90     0   0.9591   56.6
2015-07-14  18:46:52  29.19   99.6  100.0  100.0        0   90     0   0.9591   56.0
2015-07-14  18:46:53  29.08   99.7  100.0  100.0        0   90     0   0.9585   55.6
2015-07-14  18:46:54  29.19   99.6  100.0  100.0        0   91     0   0.9542   56.0
2015-07-14  18:46:55  29.24   99.6  100.0  100.0        0   92     0   0.9591   56.0
2015-07-14  18:46:56  29.29   99.5  100.0  100.0        0   92     0   0.9542   55.7
2015-07-14  18:46:57  29.28   99.6  100.0  100.0        0   93     0   0.9542   56.0
2015-07-14  18:46:58  29.27   99.6  100.0  100.0        0   92     0   0.9783   56.2
2015-07-14  18:46:59  29.28   99.5  100.0  100.0        0   93     0   0.9783   56.0
2015-07-14  18:47:00  29.38   64.3  100.0  100.0        0   63     0   1.0414   38.1
2015-07-14  18:47:01  35.11    0.7  100.0  100.0        0   58     0   1.0408    2.5
2015-07-14  18:47:02  35.31    0.4  100.0  100.0        0   55     0   1.0457    1.9
2015-07-14  18:47:03  35.19    0.4  100.0  100.0        0   53     0   1.0414    2.0

On a 4th Gen mobile CPU, Prime95 v28.5 is a beast of a program.
I think my Lenovo Y510P is worse. A 35C increase in 1 second.