Linux runs hotter than Windows?

Yes · 2011-04-10 15:58:05

Right now in Windows, CoreTemp reports that my processor is a little under 50 C, but in Arch lm-sensors says that it stays around the upper 50s, often jumping up into the 60s when I open a new program or play a Youtube video. Does anyone know why this would be? CoreTemp reports that the CPU is running at around 1.5 GHz, but in Linux cpufreq-info reports that it's often lower, around 933 MHz.

The processor is an Intel i3 mobile, which can go up to 2.13 GHz. In a Sony Vaio, just let me know if you need any other hardware specifics.

Any ideas why Linux would be running hotter than Windows?

graysky · 2011-04-10 16:13:12

Could be the calibration point of lm_sensors differs from that of coretemp. Differences in fan speeds under each is something else to consider.

Mr.Elendig · 2011-04-10 16:16:42

Can be many reasons, freq scaling, fan control, heat by the gfx card, workload, a million other things.

infested999 · 2011-04-10 16:27:20

graysky wrote:

Could be the calibration point of lm_sensors differs from that of coretemp. Differences in fan speeds under each is something else to consider.

Yes, since temperature readings aren't just the temperature number, these programs get a number called "Distance to TJ max" from the motherboard. So for example if the "Thermal Junction" max for your CPU is 100C, and your Distance to TJ Max is 60, then you current temperature is 40C.

Some programs dont know what you thermal junction max is exactly, so they just estimate its somewhere around 100-120

Yes · 2011-04-10 16:44:30

Alright, thanks for the quick replies. The reason I want to solve this is because the fan spins way faster in Linux than Windows, and it's gotten annoying how loud it is.

The CPU frequency is the same in Linux and Windows (if not a little slower in Linux).
According to htop there's no significant workload right now.
I don't see why the graphics card would be any hotter in Linux (although I'll check that out now).
The fan is spinning way faster in Linux, so it's definitely not that Linux runs the fan slower.

Do you think it would be safe to assume lm-sensors is just over estimating the thermal junction, and I can force the fans to spin a little slower?

e: When I run sensors and get a line like this -

Core 0: +58.0°C (high = +80.0°C, crit = +90.0°C)

The crit temperature is TJunction, right?

Last edited by Yes (2011-04-10 17:19:06)

Mr.Elendig · 2011-04-10 18:15:47

Btw, if it's an intel cpu, use coretemp as the source, not acpi.

(load coretemp module)

Gusar · 2011-04-10 18:15:58

What does powertop say? Is the processor scaling down, is it entering deep C states? Also, what graphic card and which driver is driving it?

Yes · 2011-04-10 18:31:35

Yeah, I'm getting the temps with the coretemp module.

Powertop says that the processor is running at 1333 MHz most of the time. I'm not sure what a deep C state is, how would I know what state it was in?

It's a Radeon 5450, I think. I'm using the opensoruce xf86-video-ati drivers.

l'pc · 2011-04-10 18:34:00

I have an other possibility... Does it have switchable graphics (2 graphics cards) ?

If it is the case, the two of them are running by default, which causes a lot of heat (~10°C more) and battery drain.
Unfortunately, they aren't any real solutions; a workaround is is using acpi calls to poweroff the second one. http://linux-hybrid-graphics.blogspot.c … -acpi.html

Last edited by l'pc (2011-04-10 18:36:51)

Yes · 2011-04-10 18:48:26

I don't think I do - according to Wikipedia my processor has a "graphics controller" build in, but that's not the same as another graphics card right?

infested999 · 2011-04-10 18:53:51

Yes wrote:

I don't think I do - according to Wikipedia my processor has a "graphics controller" build in, but that's not the same as another graphics card right?

That's the new line of Intel Integrated Graphics, the graphics card is built inside the CPU.

Most likely there is no other graphics card in that laptop.

Yes · 2011-04-10 19:12:34

Ah, it looks like the Arrandale CPUs do have integrated GPUs in them. I'll look into disabling it then.

Gusar · 2011-04-10 19:40:28

Yes wrote:

I'm not sure what a deep C state is, how would I know what state it was in?

Powertop reports C states. The CPU should spend most of it's time in the deepest - the one with the highest number.

Yes wrote:

It's a Radeon 5450, I think. I'm using the opensoruce xf86-video-ati drivers.

Power management in the radeon driver is still pretty new, it could be the graphic card is running at full performance all the time. It's possible to select power management profiles, search for how to do that.

Yes · 2011-04-10 22:26:11

I read the ATI wiki page and put the lines into xorg.conf which is supposed to enable performance switching, but the temps haven't changed. According to Xorg.0.log the settings were enabled correctly.

l'pc · 2011-04-11 09:18:52

To see if you have two graphics card, just check the output of "lspci | grep VGA". You should only get one line.

The link I provided earlier is the only way I found to switch the second graphic card off -- unfortunately linux support of 2 graphics card is pretty poor for the moment, and it seems it would be very difficult to implement it in X...

Yes · 2011-04-11 17:38:15

Ah nevermind then, I don't have a second graphics card. lspci only lists the ATI card.

Arch Linux

#1 2011-04-10 15:58:05

Linux runs hotter than Windows?

#2 2011-04-10 16:13:12

Re: Linux runs hotter than Windows?

#3 2011-04-10 16:16:42

Re: Linux runs hotter than Windows?

#4 2011-04-10 16:27:20

Re: Linux runs hotter than Windows?

#5 2011-04-10 16:44:30

Re: Linux runs hotter than Windows?

#6 2011-04-10 18:15:47

Re: Linux runs hotter than Windows?

#7 2011-04-10 18:15:58

Re: Linux runs hotter than Windows?

#8 2011-04-10 18:31:35

Re: Linux runs hotter than Windows?

#9 2011-04-10 18:34:00

Re: Linux runs hotter than Windows?

#10 2011-04-10 18:48:26

Re: Linux runs hotter than Windows?

#11 2011-04-10 18:53:51

Re: Linux runs hotter than Windows?

#12 2011-04-10 19:12:34

Re: Linux runs hotter than Windows?

#13 2011-04-10 19:40:28

Re: Linux runs hotter than Windows?

#14 2011-04-10 22:26:11

Re: Linux runs hotter than Windows?

#15 2011-04-11 09:18:52

Re: Linux runs hotter than Windows?

#16 2011-04-11 17:38:15

Re: Linux runs hotter than Windows?

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