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vaenby 01-24-2014 08:24 PM

Laptop overheating especially when compiling package
 
Hi all fellow slackers, I have a problem with my laptop. When idle, the temperature (I know it using tlp-stat -t command) is around 65 degree Celcius and when compiling my laptop it's around 85 degree and sometimes it just shutdown because it overheated. Probably the temperature is more than 100 degree.

Some information about my system:
  • My laptop is HP 431 with graphic card Radeon HD 6470M. I tried to use the newest propietary driver from AMD but I uninstalled it because it's kind of messy when I use it using dual monitor. I tried to config it using aticonfig --initial=dual-head --screen-layout=left
    but still no luck.
  • I use generic kernel as instructed in http://docs.slackware.com/slackware:beginners_guide
  • I use slackware64-14.1

My lsmod output:
Code:

Module                  Size  Used by
ipv6                  292446  30
cpufreq_ondemand        8799  0
lp                      9851  0
ppdev                  5862  0
parport_pc            19332  0
parport                30389  3 lp,ppdev,parport_pc
fan                    2617  0
fuse                  73848  7
amd_iommu_v2            7116  0
uvcvideo              71742  0
videobuf2_vmalloc      2912  1 uvcvideo
videobuf2_memops        1879  1 videobuf2_vmalloc
videobuf2_core        27437  1 uvcvideo
videodev              102061  2 uvcvideo,videobuf2_core
i2c_dev                5843  0
ath3k                  6877  0
btusb                  16152  0
bluetooth            220516  3 ath3k,btusb
nvram                  5780  0
radeon                807879  1
i915                  567446  3
intel_powerclamp        8391  0
ath9k                  87291  0
ath9k_common            1951  1 ath9k
ath9k_hw              369458  2 ath9k_common,ath9k
intel_agp              10864  1 i915
joydev                  9751  0
ttm                    63381  1 radeon
coretemp                5870  0
ath                    15545  3 ath9k_common,ath9k,ath9k_hw
snd_hda_codec_hdmi    29622  1
intel_gtt              12600  2 i915,intel_agp
mac80211              429423  1 ath9k
snd_hda_codec_realtek    34792  1
rtsx_pci_sdmmc          9505  0
snd_hda_intel          34861  5
snd_hda_codec        143196  3 snd_hda_codec_realtek,snd_hda_codec_hdmi,snd_hda_intel
cfg80211              380228  3 ath,ath9k,mac80211
drm_kms_helper        35118  2 i915,radeon
r8169                  57775  0
drm                  229054  7 ttm,i915,drm_kms_helper,radeon
mmc_core              88717  1 rtsx_pci_sdmmc
rtsx_pci_ms            5138  0
mei_me                  7728  0
mperf                  1163  0
memstick                6640  1 rtsx_pci_ms
mei                    42963  1 mei_me
processor              27543  0
thermal                8644  0
snd_hwdep              6388  1 snd_hda_codec
snd_pcm                76009  4 snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel
snd_page_alloc          7098  2 snd_pcm,snd_hda_intel
snd_timer              18614  2 snd_pcm
snd                    58630  15 snd_hda_codec_realtek,snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_pcm,snd_hda_codec,snd_hda_intel
i2c_i801              13860  0
hp_wmi                  7264  0
agpgart                27267  4 drm,ttm,intel_agp,intel_gtt
soundcore              5354  1 snd
video                  11451  1 i915
thermal_sys            22993  5 fan,video,intel_powerclamp,thermal,processor
i2c_algo_bit            5351  2 i915,radeon
i2c_core              20936  8 drm,i915,i2c_i801,i2c_dev,drm_kms_helper,i2c_algo_bit,radeon,videodev
psmouse                81058  0
sparse_keymap          3074  1 hp_wmi
rfkill                15522  5 cfg80211,hp_wmi,bluetooth
freq_table              2628  2 cpufreq_ondemand,thermal_sys
hwmon                  1337  3 coretemp,radeon,thermal_sys
mii                    3955  1 r8169
evdev                  10032  12
lpc_ich                12841  0
rtsx_pci              22092  2 rtsx_pci_ms,rtsx_pci_sdmmc
battery                11579  0
button                  4696  1 i915
ac                      4311  0
serio_raw              4585  0
kvm                  363491  0
crc32_pclmul            2883  0
crc32c_intel          14113  0
ghash_clmulni_intel    4333  0
wmi                    8243  1 hp_wmi
microcode              13140  0
loop                  18479  0
ext4                  446312  2
jbd2                  76403  1 ext4
mbcache                5666  1 ext4
hid_generic            1145  0
usbhid                37080  0
hid                    87523  2 hid_generic,usbhid
ehci_pci                3688  0
ehci_hcd              39275  1 ehci_pci
usb_storage            46020  0

I use TLP package but I don't change anything in /etc/default/tlp because I don't understand what to change there.

Any help will be much appreciated. Thanks :)

Didier Spaier 01-24-2014 10:28 PM

Someone will probably suggest to clean dust and change the thermal paste if possible. As I had the same problem I ended up getting a cooler (Zalman ZM-NC1500B). Its not expensive (I paid 32€95 including 19.6% VAT in Paris) nor too noisy and does the job.

vaenby 01-24-2014 10:35 PM

Quote:

Originally Posted by Didier Spaier (Post 5104804)
Someone will probably suggest to clean dust and change the thermal paste if possible. As I had the same problem I ended up getting a cooler (Zalman ZM-NC1500B). Its not expensive (I paid 32€95 including 19.6% VAT in Paris) nor too noisy and does the job.

What was the temperature of your laptop before and after using the cooler? I already cleaned the dust, not much effect there. About the thermal paste, the fan is quite new. About 5 or 6 months ago I got a replacement for the fan because there was a problem before with the fan and HP replaced it.

zrdc28 01-24-2014 10:55 PM

i8kutils from slackbuilds solved the problem on my dell laptop, might work on yours too.

vaenby 01-25-2014 12:01 AM

Quote:

Originally Posted by zrdc28 (Post 5104811)
i8kutils from slackbuilds solved the problem on my dell laptop, might work on yours too.


Mine is HP laptop. i8kutils is for dell :(

freakTux 01-25-2014 01:57 AM

Quote:

Originally Posted by vaenby (Post 5104828)
Mine is HP laptop. i8kutils is for dell :(

I don't know how Dell is...but I can say that Asus (that I like so much) is a little strange...I had overheating problem with my notebook, so I replace the thermal paste...I can say that even if the notebook was pretty new, the way how the thermal paste was applied was very sick and after the replacement the temperature was 10 degrees under...XD...the thermal paste is much more important than the dust inside...Check it and you'll be surprised...

TobiSGD 01-25-2014 02:04 AM

This is a software problem. While replacing the thermal paste and cleaning out the cooling system isn't a bad thing, it will not fix the overheating.

The problem is that you use the Slackware kernel. The 3.10 kernel lacks dynamic power management for your videocard, so that it by default always runs on full power, heating up the system. Install a 3.13 kernel, which has dynamic power management enabled by default and you should immediately see much better temperatures.

Didier Spaier 01-25-2014 02:56 AM

Quote:

Originally Posted by vaenby (Post 5104805)
What was the temperature of your laptop before and after using the cooler? I already cleaned the dust, not much effect there. About the thermal paste, the fan is quite new. About 5 or 6 months ago I got a replacement for the fan because there was a problem before with the fan and HP replaced it.

I didn't measure the temperature after using the cooler.

But what I know for sure is that I use the cooler whenever I use a VM or do demanding compilations and the laptop doesn't get hot anymore. I hope that'll extend its life several of several years.

Of course you can try a 3.13 kernel, as TobiSGD suggested (though it be fairly new so if that was me I would wait a few weeks till it has been more widely used so possibly some more bugs in it will be fixed).

Notwithstanding I think it's a shame that we can't use our laptops at their full potential without overheating, but that's another topic.

TobiSGD 01-25-2014 04:21 AM

Quote:

Originally Posted by Didier Spaier (Post 5104864)
Notwithstanding I think it's a shame that we can't use our laptops at their full potential without overheating, but that's another topic.

If I had such a laptop I would return it to vendor, since this clearly is a problem with its design. Regardless which OS or which applications you use, there is only a certain amount of heat a system can produce under load (thermal design power). If your cooling system is not able to transport that heat away reliably it is poorly designed.

enorbet 01-25-2014 04:46 AM

Or poorly assembled. I have seen brand name laptops in which the heatsink did not make firm contact with the CPU. Others must resort to overly thick so-called thermal paste tabs with dbl-sided adhesive. Ridiculous. Even the best designed laptops rarely like to have holes, even as grillework, so airflow is not at a premium.... looks are. This is horrible too. Anything you can do to improve heat transfer is smart work. Even a copper shim between HS and CPU with proper thermal compound, can make your laptop more usable and for a lot longer, if poorly designed or assembled. Sadly, many consumer laptops are both.

schmatzler 01-25-2014 05:38 AM

Quote:

Originally Posted by enorbet (Post 5104906)
Others must resort to overly thick so-called thermal paste tabs with dbl-sided adhesive. Ridiculous.

And it is a "pure coincidence" that these tabs are drying out so the notebook gets unusable shortly after the end of the warranty period.

That reminds me of the mobile desaster that NVIDIA had with their G84 or NVS135M graphic chips. The first bunch they produced failed when they reached 90 degrees or above, so NVIDIA had to produce a new one that could withstand the heat.

A better option would have been to just produce notebooks that don't behave like microwaves - but that would have been to easy.

I have an old Fujitsu notebook here with a chip from the first (faulty) series. It is never reaching these high temperatures and playing games is no problem on that device.

On the other hand, a Dell D630 with the same chip failed two times (the second time after two weeks).

At least there are still good notebooks out there with a good coolant system. You just have to look. The Thinkpad series from Lenovo is still one of the most reliable in my opinion.

Claudiu.Ionel 01-25-2014 05:21 PM

reduce heat
 
From what I have seen with my Dell D630 from 2007:
-overheating is caused by heavy graphics, desktop environment, cpu demanding programs.
-you use the nouveau video drivers and this is hotter by ~10°C , use the proprietary drivers instead. Find an older version if the newest is causing problems.
-try the 3.2.53 kernel
- and almost forgot but you can use the jfs file system and you will get lower cpu usage (lower temps) than ext4 .
-you can try to underclock the cpu a little and not letting it to go to max all the time by adding this to /etc/rc.d/rc.local :


cpufreq-set --cpu 0 --max 1200000
cpufreq-set --cpu 1 --max 1200000

After setting the max frequency for ondemand governor now I read from sensors:
temp1: +34.5°C (crit = +99.0°C)

PS: If you tweak the cpu frequency to minimum you don't have to worry about heat anymore :)

metaschima 01-25-2014 05:41 PM

All the right modules are modprobed, so I suspect a hardware issue. Probably the fans are clogged with dust, and you may want to use compressed air to clean all the air ports. As this is a laptop, I do NOT recommend taking it apart. If the problem persists I would ask the manufacturer about the issue.

enorbet 01-25-2014 06:27 PM

Quote:

Originally Posted by metaschima (Post 5105241)
<snip> As this is a laptop, I do NOT recommend taking it apart. <snip>

The above advice is generally wise since we can only guess at someone else's electro-mechanical experience and expertise. However there are a few situations when you should throw such advice out the window and just fix it yourself, or at least see how it's built and what could be wrong.

If it is out of warranty or you don't care about warranty.
If it is not your main or a production machine, or you have a backup machine.
If you're just sick of risking sterility everytime you actually place it on your lap and the manufacturer won't do anything about it.

Laptops are not rocket surgery. Like a PC all the components are keyed so they only go together one way. As long as you pay attention to the order that things disassemble and don't just yank on wires but grasp the connectors and activate any obvious locking mechanism disassembly is no big deal for anyone with even moderate mechanical skills. The only gotcha here is that sometimes manufacturers cover up the locations of bolts or screws with adhesive labels - not that big of a deal to discover and defeat.

Re-Assembly just requires not overtightening into plastic, brass or aluminum and it isn't a bad idea to use the crosshatch method of applying torque evenly. Do it in diagonals a step at a time and it's easy peasy.

The most important thing to remember and follow in both steps is to use the right tools. Don't try to use a Phillips Screwdriver that is too big or too small for a bolt head. I really don't have to say don't use a flat blade on a phillips do I? If your laptop uses Torx heads, stop, and do not continue until you have the proper tool. For most people as long as you don't rush, you will be just fine. Just think it through before you commit to an action. There is no shame in putting it back together and thinking about it for a few days while you re-evaluate your skills to go any further.

Obviously if you decide to do this the responsibility is all yours but there is a lot of help on the Net, including here. A big plus is de-mystifying your lil' lap buddy. It's just a machine and one that is built to be easily assembled on a line. Not magic.

ReaperX7 01-25-2014 08:04 PM

Since you have a laptop, you might also want to search Slackbuilds for Laptop related tools to manage fan controls, power usage, and other laptop related factors.

laptop-mode-tools is a must have, as is ibam, and maybe wmpower, all of which are available from www.slackbuilds.org website.

metaschima 01-25-2014 08:05 PM

If you are sure that it is a hardware issue, the manufacturer won't help, it is out of warranty and you have some skill, then you could open it. I would take a camera to record each step, because putting it back together is gonna be hard. You may also want to find a tear-down video / howto before you start.

cascade9 01-26-2014 06:26 AM

Quote:

Originally Posted by enorbet (Post 5104906)
Or poorly assembled. I have seen brand name laptops in which the heatsink did not make firm contact with the CPU. Others must resort to overly thick so-called thermal paste tabs with dbl-sided adhesive.
Snip!
Anything you can do to improve heat transfer is smart work. Even a copper shim between HS and CPU with proper thermal compound, can make your laptop more usable and for a lot longer, if poorly designed or assembled. Sadly, many consumer laptops are both.

If there is a large space between the heatsink and the CPU, maybe a shim would be a good idea. Aside from that (hopefully) rare situation, shims will make thinsg worse. But with the 'race to the bottom', 'cheap as the manufacturer can get away with' laptops, it might be far more common than in better laptops or desktops.

Quote:

Originally Posted by Claudiu.Ionel (Post 5105227)
From what I have seen with my Dell D630 from 2007:
-overheating is caused by heavy graphics, desktop environment, cpu demanding programs.
-you use the nouveau video drivers and this is hotter by ~10°C , use the proprietary drivers instead. Find an older version if the newest is causing problems.
-try the 3.2.53 kernel
- and almost forgot but you can use the jfs file system and you will get lower cpu usage (lower temps) than ext4 .
-you can try to underclock the cpu a little and not letting it to go to max all the time by adding this to /etc/rc.d/rc.local :


cpufreq-set --cpu 0 --max 1200000
cpufreq-set --cpu 1 --max 1200000

After setting the max frequency for ondemand governor now I read from sensors:
temp1: +34.5°C (crit = +99.0°C)

PS: If you tweak the cpu frequency to minimum you don't have to worry about heat anymore :)

IMO the cause of overheating in this laptop is the 'switchable graphics' setup..the Radeon HD 6470M is probably just drawing power and creating heat pointlessly.

Underclocking the CPU, gah. By aprox 50% as well, thats _really_ going to hurt performance. It might help overheating when compiling, but that is ignoring the real problem...and its quite likely the laptop will still overheat.

Quote:

Originally Posted by schmatzler (Post 5104921)
That reminds me of the mobile desaster that NVIDIA had with their G84 or NVS135M graphic chips. The first bunch they produced failed when they reached 90 degrees or above, so NVIDIA had to produce a new one that could withstand the heat.

Just FYI, that was 'bumpgate', and not just limited to mobile GPUs, it also affected desktop GPUs. They never totally fixed the problems with G7X, G8X and G9X.

Also, NVS 135 is G84M, and basicly the same chip as used in the 8400M G/GS/GT.

vaenby 01-26-2014 07:53 AM

Quote:

Originally Posted by TobiSGD (Post 5104852)
This is a software problem. While replacing the thermal paste and cleaning out the cooling system isn't a bad thing, it will not fix the overheating.

The problem is that you use the Slackware kernel. The 3.10 kernel lacks dynamic power management for your videocard, so that it by default always runs on full power, heating up the system. Install a 3.13 kernel, which has dynamic power management enabled by default and you should immediately see much better temperatures.

Does it mean I need to compile the 3.13 kernel myself? I don't have experience doing that. Isn't it hard to do? :(

Quote:

Originally Posted by Claudiu.Ionel (Post 5105227)
From what I have seen with my Dell D630 from 2007:
-overheating is caused by heavy graphics, desktop environment, cpu demanding programs.
-you use the nouveau video drivers and this is hotter by ~10°C , use the proprietary drivers instead. Find an older version if the newest is causing problems.
-try the 3.2.53 kernel
- and almost forgot but you can use the jfs file system and you will get lower cpu usage (lower temps) than ext4 .
-you can try to underclock the cpu a little and not letting it to go to max all the time by adding this to /etc/rc.d/rc.local :


cpufreq-set --cpu 0 --max 1200000
cpufreq-set --cpu 1 --max 1200000

After setting the max frequency for ondemand governor now I read from sensors:
temp1: +34.5°C (crit = +99.0°C)

PS: If you tweak the cpu frequency to minimum you don't have to worry about heat anymore :)

Yes, that's what I thought too. I think I'll try to install the 2nd newest propietary driver first. Btw what do the commands do?

enorbet 01-26-2014 10:45 AM

OP go from general to specific. Either narrow down the cause (best) or eliminate all possible causes (weak, but workable)

Quote:

Originally Posted by cascade9 (Post 5105451)
IMO the cause of overheating in this laptop is the 'switchable graphics' setup..the Radeon HD 6470M is probably just drawing power and creating heat pointlessly.

I am unfamiliar with this runaway problem with switchable graphics so all I can say is either meter this to be certain this is happening or if there is a simple software fix, try it and see if the temps drop. Software problems should be addressed first especially if it is not in a "from the factory" condition ie - you installed a new system. Fix this first because it is easier and faster to see results.

It can also be worthwhile just to remove the battery if you expect a long term on AC power, or as OP mentioned, during a particularly intense task on AC.


Quote:

Originally Posted by cascade9 (Post 5105451)
If there is a large space between the heatsink and the CPU, maybe a shim would be a good idea. Aside from that (hopefully) rare situation, shims will make thinsg worse. But with the 'race to the bottom', 'cheap as the manufacturer can get away with' laptops, it might be far more common than in better laptops or desktops.

If, OTOH, it is hardware related that isn't as hard to fix as many think. Regarding the above, I emphatically disagree. There can be NO SPACE between a heat sink and the heat source because air is an insulator. I have never seen nor can I even imagine how a proper shim to take up an air gap could ever possibly "make things worse". There are even videos on YouTube showing how to do this. It is that common, and as I said it isn't beyond the scope of even moderate skills.

In addition to making certain there is good heat transfer between the CPU and it's heatsink (and also the GPU and it's, if it has one) one should look to see if there is any obvious spot to improve airflow. Just don't drill any holes, especially in metal, without the means to insure complete and utter clean up afterwards. A Nibbler on plastic works wonders and a thin sheet of packing foam can act as a filter and cosmetic cover if you decide to add what amounts to a new air intake.

If you have a good reason not to modify your hardware, even fear, then just don't, but for most people with any decent tools and skills to use them, the improvement can be absolutely dramatic. I have seen 20 C reductions at idle, and far greater resistance to change under load. Just more stable.

Quote:

Originally Posted by cascade9 (Post 5105451)
Underclocking the CPU, gah. By aprox 50% as well, thats _really_ going to hurt performance. It might help overheating when compiling, but that is ignoring the real problem...and its quite likely the laptop will still overheat.

Other than for testing I wholeheartedly agree with the above. Castrating your CPU should not be a viable solution when other means exist.

enine 01-26-2014 06:19 PM

Quote:

Originally Posted by Claudiu.Ionel (Post 5105227)
From what I have seen with my Dell D630 from 2007:
-overheating is caused by heavy graphics, desktop environment, cpu demanding programs.
-you use the nouveau video drivers and this is hotter by ~10°C , use the proprietary drivers instead. Find an older version if the newest is causing problems.
-try the 3.2.53 kernel
- and almost forgot but you can use the jfs file system and you will get lower cpu usage (lower temps) than ext4 .
-you can try to underclock the cpu a little and not letting it to go to max all the time by adding this to /etc/rc.d/rc.local :


cpufreq-set --cpu 0 --max 1200000
cpufreq-set --cpu 1 --max 1200000

After setting the max frequency for ondemand governor now I read from sensors:
temp1: +34.5°C (crit = +99.0°C)

PS: If you tweak the cpu frequency to minimum you don't have to worry about heat anymore :)

Interesting to note that I have a D630, two D620's and a couple C series. Each one has gotten too hot and I've start to disassemble and replace the paste and clean the fan when I get them, all bought used. My belief is that Windows never reaches the full potential. The D620/630 have the gap between the fan and the fins on the heat pipe that fills with hair, dust, etc.

colorpurple21859 01-26-2014 07:52 PM

check this out http://www.linuxquestions.org/questi...8/#post4830372

TobiSGD 01-26-2014 10:52 PM

Quote:

Originally Posted by vaenby (Post 5105479)
Does it mean I need to compile the 3.13 kernel myself? I don't have experience doing that. Isn't it hard to do? :(

Actually, it is pretty easy. AlienBob has a nice HowTo for that (of course you have to adapt the kernel version): http://alien.slackbook.org/dokuwiki/...kernelbuilding

cascade9 01-27-2014 03:11 AM

Quote:

Originally Posted by enorbet (Post 5105556)
If, OTOH, it is hardware related that isn't as hard to fix as many think. Regarding the above, I emphatically disagree. There can be NO SPACE between a heat sink and the heat source because air is an insulator. I have never seen nor can I even imagine how a proper shim to take up an air gap could ever possibly "make things worse". There are even videos on YouTube showing how to do this. It is that common, and as I said it isn't beyond the scope of even moderate skills.

Umm...'air gap' is a bit of an overstatement. Though it can happen, as some heatsinks are slightly curved, cheap ones in particular. In those cases while there will be contact between the CPU and theheatsink, its not full contact, and there can be 'air gaps' at the sides of the CPU/heatsink interface.

Its also possible that there will not be enough pressure on the heatsink, and in those cases adding a shim can help.

Adding a shim in most (all?) other cases just adds more layers and more thermal paste, which reduces the efficiency of the cooling system.

Quote:

Originally Posted by enorbet (Post 5105556)
I am unfamiliar with this runaway problem with switchable graphics so all I can say is either meter this to be certain this is happening or if there is a simple software fix, try it and see if the temps drop. Software problems should be addressed first especially if it is not in a "from the factory" condition ie - you installed a new system. Fix this first because it is easier and faster to see results.

Its not really runaway. The issue is that with switcahble graphics setups, the 'unused' video adapter is generally not 'switched off' with linux, which just sucks power and creates heat.

Its fixable in most Intel CPU/AMD GPU or AMD CPU/AMD GPU situations with vgaswitcharoo or by using the fglrx closed driver. (Intel CPU/nVidia GPU and AMD CPU/nVidia GPU setups are now almost always 'optimus' and work better with bumblebee).

enorbet 01-27-2014 05:02 AM

Just some comments for clarity

Quote:

Originally Posted by cascade9 (Post 5105937)
Its not really runaway. The issue is that with switcahble graphics setups, the 'unused' video adapter is generally not 'switched off' with linux, which just sucks power and creates heat.

Its fixable in most Intel CPU/AMD GPU or AMD CPU/AMD GPU situations with vgaswitcharoo or by using the fglrx closed driver. (Intel CPU/nVidia GPU and AMD CPU/nVidia GPU setups are now almost always 'optimus' and work better with bumblebee).

I do know enough about switcheroo, bumblebee(d) et al that I know it isn't really a runaway. I'm afraid that choice of words just reflects a near obsession with thermals. To me 65 C idle is just insanely hot and completely unusable in that condition, requiring an immediate and if needed, drastic fix.

Quote:

Originally Posted by cascade9 (Post 5105937)
Umm...'air gap' is a bit of an overstatement. Though it can happen, as some heatsinks are slightly curved, cheap ones in particular. In those cases while there will be contact between the CPU and theheatsink, its not full contact, and there can be 'air gaps' at the sides of the CPU/heatsink interface.

Its also possible that there will not be enough pressure on the heatsink, and in those cases adding a shim can help.

Adding a shim in most (all?) other cases just adds more layers and more thermal paste, which reduces the efficiency of the cooling system.

I am fully aware and extremely experienced with heatsinks and thermal removal systems of many varieties including passive, water, oil, and phase change as well as electrical (ie- Peltier). "Air Gap" is not an overstatement for this reason as I am not referring to the minute differences in surface flatness/smoothness. That requires polishing, which I commonly do on PCs but is of little value on a laptop due to most having CPUs soldered in place, making the risk not worth the gain.

The occurrence of an actual and substantial air gap on many laptops is due to factory assembly methods. Parts that fit together precisely are generally anathema to assembly line speed, so manufacturers often resort to extremely thick wafers of "thermal pads". This is at best, "fooling oneself" since even the best thermal paste does not have a coefficient even approaching metal to metal contact. It's just better than air. Thermal paste should be applied in as thin a layer as possible. Ideally much of the mating surfaces should NOT be separated by paste so that it only fills the low spots preventing air pockets.

It is not uncommon to see thermal wafers used that are 1/16th inches thick (0.0625) and I have witnessed some closer to 1/8th inch (0.125). It is only a very slight improvement to replace this entire thickness with the same thickness of even high quality thermal paste, the primary benefit being simply eliminating the adhesive layers on both sides. Not the best improvement, but some.

Consider this: A person could coat his finger tip with a thick layer of thermal paste and apply a match to it with very little danger of a burn. DO NOT try that with a copper shim with a thin layer on both sides. Does that make it more real for you?.

A less dramatic test that is safer to try is this. Put a blob of thermal paste, or better one of those ridiculous wafers, on a nonflammable surface and hold a match or a lighter to it for say, 5 full seconds. The blob, if the mass approaches anywhere near the amount actually used on many laptop heatsinks, will not even be uncomfortably warm in 5 seconds. A wafer can get uncomfortable but not deliver a burn even though the adhesive will ignite and burn for a few seconds too, and in direct intimate contact with the paste. Again, DO NOT try this with a shim of similar mass with a thin layer of paste.

FTR, I have done both of these tests, but only after I employed a VOM with a thermal transducer probe to measure actual temps. (I may be crazy but I'm not an idiot :P ) Heat in electronics is the enemy and I take it very seriously, and defeat it with extreme prejudice and knowledge gained from many years of work in the field.

You do what you want, but I will never own for long any electronics (other than Vacuum Tube) that will idle at 65 C.

cascade9 01-27-2014 06:00 AM

Quote:

Originally Posted by enorbet (Post 5105999)
I am fully aware and extremely experienced with heatsinks and thermal removal systems of many varieties including passive, water, oil, and phase change as well as electrical (ie- Peltier). "Air Gap" is not an overstatement for this reason as I am not referring to the minute differences in surface flatness/smoothness. That requires polishing, which I commonly do on PCs but is of little value on a laptop due to most having CPUs soldered in place, making the risk not worth the gain.

I wouldnt call imperfections in the heatsink an 'air gap'. If the heatsink and/or CPU heatspreader is not flat, you can get what I'd call an air gap.

BTW, its normally called 'lapping', not 'polishing'.

Quote:

Originally Posted by enorbet (Post 5105999)
The occurrence of an actual and substantial air gap on many laptops is due to factory assembly methods. Parts that fit together precisely are generally anathema to assembly line speed, so manufacturers often resort to extremely thick wafers of "thermal pads". This is at best, "fooling oneself" since even the best thermal paste does not have a coefficient even approaching metal to metal contact. It's just better than air. Thermal paste should be applied in as thin a layer as possible. Ideally much of the mating surfaces should NOT be separated by paste so that it only fills the low spots preventing air pockets.

Thermal pads can and do compress. Sure, if there is flatness issues you will get thick bits...and if a manufacturer is using a really badly fitted and/or designed heatsink you can get some quite thick bits of thermal pad.

But that is bad design and bad manufacturing.

I seen lots of people suggest shims over the years, and sometimes I've seen people even say 'adding a shim will help in all situations becasue copper conducts heat better than aluminium'. Thats a bit silly, as you can get pure copper and copper bottomed heatsinks. But even with an aluminium heatsink, its still very uncommon to see temps go down, they mostly go up.

If there is a normal ('good' I spose) heatsink/CPU interface, adding a shim will just make things worse. The more thickness and layers you have, the harder it is for the heat to get out. That is why you can remove the intergrated heatspeader found in pretty much all current CPUs and improve temps. No, I am not suggesting that is a good idea for any normal user)

Quote:

Originally Posted by enorbet (Post 5105999)
Consider this: A person could coat his finger tip with a thick layer of thermal paste and apply a match to it with very little danger of a burn. DO NOT try that with a copper shim with a thin layer on both sides. Does that make it more real for you?.

Its not going to be as hot as just a thin layer of thermal paste. ;)

Quote:

Originally Posted by enorbet (Post 5105999)
You do what you want, but I will never own for long any electronics (other than Vacuum Tube) that will idle at 65 C.

Either Virginia isnt that warm, or you have aircon, or both. ;)

I ran many systems with 40C+ room temps during summer for years. At 40C+, idle temps tend to the mid to high 50s at minimum. I've had idle temps go as high as 60C+ at times. No, its not a good idea.

Quote:

Originally Posted by enorbet (Post 5105999)
I do know enough about switcheroo, bumblebee(d) et al that I know it isn't really a runaway. I'm afraid that choice of words just reflects a near obsession with thermals. To me 65 C idle is just insanely hot and completely unusable in that condition, requiring an immediate and if needed, drastic fix.

IMO its software related, and should be fixable with vgaswitchroo, and/or possibly other methods (e.g. using a 3.13 kernel as suggested by TobiSGD).

I'd be trying to reinstall windows asw a temp test and/or install vgaswitcharoo, a new kernel etc. with linux before modding hardware.

enorbet 01-27-2014 07:29 AM

Quote:

Originally Posted by cascade9 (Post 5106029)
I wouldnt call imperfections in the heatsink an 'air gap'. If the heatsink and/or CPU heatspreader is not flat, you can get what I'd call an air gap.

Ummm neither did I. I thought I made it clear that the gap comes from removing an overly thick wafer that was used by the manufacturer to keep assembly costs down. To me, 1/16 inch is far too large a gap to be spanned by thermal compound.

Quote:

Originally Posted by cascade9 (Post 5106029)
BTW, its normally called 'lapping', not 'polishing'.

Of course I am aware of the hobbyist terminology. Assume I just didn't want any beginners trying to lick their CPU. :P
<snip>
Quote:

Originally Posted by cascade9 (Post 5106029)
I seen lots of people suggest shims over the years, and sometimes I've seen people even say 'adding a shim will help in all situations becasue copper conducts heat better than aluminium'. Thats a bit silly, as you can get pure copper and copper bottomed heatsinks. But even with an aluminium heatsink, its still very uncommon to see temps go down, they mostly go up.

Those people are ignorant of the Science, and if their temps go up, they are also inept at the mechanics.

Quote:

Originally Posted by cascade9 (Post 5106029)
Its not going to be as hot as just a thin layer of thermal paste. ;)

Why even mention this? The specific comparison was between a thick layer of compound/paste vs/ 2 thin layers and a metal shim. There is no need to twist or invent things upon which to disagree.


Quote:

Originally Posted by cascade9 (Post 5106029)
Either Virginia isnt that warm, or you have aircon, or both. ;)

In the Summer, Virginia can have occasional days of 40 C but 32 C is rather common. I presently have aircon but use it conservatively and have lived or worked in locations without it. It doesn't matter. Under no circumstances would I allow idle temps of 65 C. which for reference, is the very hottest that people unconcerned about energy cost and environmental impact will set their Water Heaters. It will scald a person, so obviously we never have to deal with an ambient temp within even 10 C of that condition. There is no severe obstacle, other than obstinance or ignorance, to achieving Delta T's of less than 10 C from ambient at idle. So even at 40 C I expect and commonly get an idle no higher than 50 C. That is VERY different from 65 C.... nearly 30 F different, for those less familiar with Celsius.


Quote:

Originally Posted by cascade9 (Post 5106029)
I ran many systems with 40C+ room temps during summer for years. At 40C+, idle temps tend to the mid to high 50s at minimum. I've had idle temps go as high as 60C+ at times. No, its not a good idea.

See above and exactly! and I already agreed that software fix should come first. My intent was simply to demystify the mechanics of working on laptops. It's a bogeyman easily dispelled. Hopefully that is clearer now.

cascade9 01-28-2014 10:36 AM

Quote:

Originally Posted by enorbet (Post 5106074)
Of course I am aware of the hobbyist terminology. Assume I just didn't want any beginners trying to lick their CPU. :P

Its actually the correct terminology.

http://en.wikipedia.org/wiki/Lapping

You can 'polish' a sphere. You cant lap one. ;)

*edit- actually, technically, you can 'lap' a sphere, but spherical lapping is not the same as plate lapping.

Quote:

Originally Posted by enorbet (Post 5106074)
In the Summer, Virginia can have occasional days of 40 C but 32 C is rather common. I presently have aircon but use it conservatively and have lived or worked in locations without it. It doesn't matter. Under no circumstances would I allow idle temps of 65 C. which for reference, is the very hottest that people unconcerned about energy cost and environmental impact will set their Water Heaters. It will scald a person, so obviously we never have to deal with an ambient temp within even 10 C of that condition. There is no severe obstacle, other than obstinance or ignorance, to achieving Delta T's of less than 10 C from ambient at idle. So even at 40 C I expect and commonly get an idle no higher than 50 C. That is VERY different from 65 C.... nearly 30 F different, for those less familiar with Celsius.

You are young, arent you?

20C+ idle deltas are uncommon now thanks to CPU frequency scaling and better power management. But it used to be fairly common.

Quote:

The room temperature during the tests was 20 C.

Idle Mode
33 C (Hyper-Threading enabled)
41 C (Hyper-Threading disabled)
http://www.xbitlabs.com/articles/cpu...y/p4-temp.html

Thats a 13 C delta with Hyper-Threading, 21 C without.

Given a 40C room thats a 53C/61C idle temp.... and that is with an aftermarket heatsink, which IIRC was better than the stock P4 heatsink...

Quote:

Originally Posted by enorbet (Post 5106074)
Those people are ignorant of the Science, and if their temps go up, they are also inept at the mechanics.

You're forgetting that thermal paste isnt as good a conductor of heat as copper or aluminium.

Quote:

For comparison, the approximate thermal conductivities of various materials relevant to heatsinks in W/(m·K) are:

Air 0.024
Water 0.58
Thermal grease about 0.5 to 10
Unbranded grease typically 0.8;[1] some silver-and graphite-based greases claim about 9
Aluminum oxide (surface layer on pure aluminium exposed to air) 35
Zinc oxide (used in diaper rash ointment) 35
Steel About 40, varies for different types
Sodium Fluoride (primary active ingredient in most toothpastes) 132
Aluminum 220
Copper 390
Silver 420
Natural Diamond 2000

Snip!

All these compounds conduct heat far better than air, but far worse than metal.
http://en.wikipedia.org/wiki/Thermal_grease

'Science' says that more layers of thermal grease = worse performance.

Quote:

Originally Posted by enorbet (Post 5106074)
Ummm neither did I. I thought I made it clear that the gap comes from removing an overly thick wafer that was used by the manufacturer to keep assembly costs down. To me, 1/16 inch is far too large a gap to be spanned by thermal compound.

I think you mean 'thermal pad', and I havent seen any evidence that vaenbys laptop has a large 'gap' between the heatsink and CPU.

Quote:

Originally Posted by enorbet (Post 5106074)
Why even mention this? The specific comparison was between a thick layer of compound/paste vs/ 2 thin layers and a metal shim. There is no need to twist or invent things upon which to disagree.

Why even mention the possible manufacturer cost cutting when you have no evidence of it? Creating a dumbed down secanario doesnt make it true.


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