[lm-sensors] Wrong temperatures reported for Core2Duo CPU in Intel

[lm-sensors] Wrong temperatures reported for Core2Duo CPU in Intel

[lmsensorslist]

Hello,

I have an Intel DG965WH motherboard with an Intel Core2Duo CPU which seems
to report incorrect core temperatures:

$ sensors
coretemp-isa-0000
Adapter: ISA adapter
Core 0:      +74.0°C  (high = +86.0°C, crit = +100.0°C)

coretemp-isa-0001
Adapter: ISA adapter
Core 1:      +73.0°C  (high = +86.0°C, crit = +100.0°C)

~75C is the idle temperature; when the CPU is busy it's more like 85C, and
sometimes even 90C+.  I think this is wrong because a) that just seems
insanely high; b) the CPU heatsink is warm, not hot, to the touch; and c)
it's been running like this almost 24/7 for about 3.5 years, which I doubt
it would have survived if it were really that hot.  I also have 2 hard
disks in this PC which report ~32C and ~41C (from the hddtemp command)
which seems much more reasonable.

I originally had the Intel heatsink+fan on there, and then I switched to a
Rosewill RCX-Z300, which is supposed to be cooler and quieter.  But either
way the reported temperature is super high.  I'm also confident that
there's good contact from the heatsink to the thermal compound to the CPU,
so I don't think that's an issue.

The main reason this bothers me is that the CPU fan is always running
really fast and thus is really loud.  This drives me crazy.  Over the
years I've tried several times to solve this, to no avail; and supposedly
something from Intel was always just around the corner -- is the new Intel
QST SDK something that might help?  The "sensors" output above is the full
output from that command, so I believe my motherboard/chipset is just not
well supported at all, which I gather is due to this heretofore-secret
Intel stuff.

I've also just tried the iasl command to check/fix any DSDT issues, but it
reported 0 errors and just 1 warning, so I don't think any of that is the
problem.

Here's some of my system info:

#

$ uname -a
Linux soma 2.6.31-20-generic #57-Ubuntu SMP Mon Feb 8 09:02:26 UTC 2010
x86_64 GNU/Linux

#

$ lspci
00:00.0 Host bridge: Intel Corporation 82P965/G965 Memory Controller Hub
(rev 02)
00:02.0 VGA compatible controller: Intel Corporation 82G965 Integrated
Graphics Controller (rev 02)
00:03.0 Communication controller: Intel Corporation 82P965/G965 HECI
Controller (rev 02)
00:19.0 Ethernet controller: Intel Corporation 82566DC Gigabit Network
Connection (rev 02)
00:1a.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI
Controller #4 (rev 02)
00:1a.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI
Controller #5 (rev 02)
00:1a.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI
Controller #2 (rev 02)
00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio
Controller (rev 02)
00:1c.0 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express
Port 1 (rev 02)
00:1c.1 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express
Port 2 (rev 02)
00:1c.2 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express
Port 3 (rev 02)
00:1c.3 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express
Port 4 (rev 02)
00:1c.4 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express
Port 5 (rev 02)
00:1d.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI
Controller #1 (rev 02)
00:1d.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI
Controller #2 (rev 02)
00:1d.2 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI
Controller #3 (rev 02)
00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI
Controller #1 (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev f2)
00:1f.0 ISA bridge: Intel Corporation 82801HH (ICH8DH) LPC Interface
Controller (rev 02)
00:1f.2 IDE interface: Intel Corporation 82801H (ICH8 Family) 4 port SATA
IDE Controller (rev 02)
00:1f.3 SMBus: Intel Corporation 82801H (ICH8 Family) SMBus Controller
(rev 02)
00:1f.5 IDE interface: Intel Corporation 82801H (ICH8 Family) 2 port SATA
IDE Controller (rev 02)
02:00.0 IDE interface: Marvell Technology Group Ltd. 88SE6101 single-port
PATA133 interface (rev b1)
06:03.0 FireWire (IEEE 1394): Texas Instruments TSB43AB22/A
IEEE-1394a-2000 Controller (PHY/Link)

#

I'm running the latest BIOS (MQ96510J.86A.1754.2008.1117.0002), and there
hasn't been an update for over a year.

If anyone can shed any light on this, in particular how I can get the fan
to spin slower or (even better) get these temperatures to be correct, I
would really appreciate it.

Thanks,

--
Anthony DiSante
http://nodivisions.com/



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Re: [lm-sensors] Wrong temperatures reported for Core2Duo CPU in

[Jean Delvare]

Hi Anthony,

On Tue, 9 Mar 2010 18:28:10 -0800, lmsensorslist@nodivisions.com wrote:
> Hello,
> 
> I have an Intel DG965WH motherboard with an Intel Core2Duo CPU which seems
> to report incorrect core temperatures:
> 
> $ sensors
> coretemp-isa-0000
> Adapter: ISA adapter
> Core 0:      +74.0°C  (high = +86.0°C, crit = +100.0°C)
> 
> coretemp-isa-0001
> Adapter: ISA adapter
> Core 1:      +73.0°C  (high = +86.0°C, crit = +100.0°C)
> 
> ~75C is the idle temperature; when the CPU is busy it's more like 85C, and
> sometimes even 90C+.  I think this is wrong because a) that just seems
> insanely high; b) the CPU heatsink is warm, not hot, to the touch; and c)
> it's been running like this almost 24/7 for about 3.5 years, which I doubt
> it would have survived if it were really that hot.  I also have 2 hard
> disks in this PC which report ~32C and ~41C (from the hddtemp command)
> which seems much more reasonable.

The value is reported by the CPU itself. The coretemp kernel driver is
just passing it through. While the value is reported relative to the
critical limit, and we have had this critical limit wrong for some
models in the past, this is irrelevant here: the fact is that your CPU
runs over its high limit when loaded. I've never seen any Intel Core2
CPU reaching such a high temperature. This can mean only 2 things:
* You happen to have a CPU with defective thermal sensors. The fact
  that both cores agree makes me skeptical, but then again, as I have
  no idea how the internal sensors could go wrong, it might as well
  happen to both sensors at once.
* Your heatsink and fan are not doing their job properly. This is my
  favorite theory at this point.

I would not be surprised that the CPU survives 3.5 years at these
temperatures. You are still below the critical limit.

Hard disk drive temperature is a totally different thing. Assuming
there is some space between the CPU and the HDD (and there always is on
a desktop board) there is no reason for these temperature to match.

> I originally had the Intel heatsink+fan on there, and then I switched to a
> Rosewill RCX-Z300, which is supposed to be cooler and quieter.  But either
> way the reported temperature is super high.  I'm also confident that
> there's good contact from the heatsink to the thermal compound to the CPU,
> so I don't think that's an issue.

This is the most likely problem though.

> The main reason this bothers me is that the CPU fan is always running
> really fast and thus is really loud.  This drives me crazy.  Over the
> years I've tried several times to solve this, to no avail; and supposedly
> something from Intel was always just around the corner -- is the new Intel
> QST SDK something that might help?  The "sensors" output above is the full
> output from that command, so I believe my motherboard/chipset is just not
> well supported at all, which I gather is due to this heretofore-secret
> Intel stuff.

The QST SDK might let us provide support for motherboard sensors, but
this will not change the values reported by the coretemp driver. Best
you can hope is extra temperature sensors for comparison purpose.
However, as for the HDD temperature sensors, sensors placed on a
different location on the motherboard don't tell you much about the CPU
temperature.

What you can do is check the temperatures reported by the BIOS. It's
difficult to know where the BIOS gets the values from, though...

> (...)
> If anyone can shed any light on this, in particular how I can get the fan
> to spin slower or (even better) get these temperatures to be correct, I
> would really appreciate it.

Fan control is not possible with only the coretemp driver, sorry. You
might look in the BIOS options for an automatic fan speed control
option, but given how hot your CPU already is, I wouldn't dare enabling
it.

-- 
Jean Delvare

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Re: [lm-sensors] Wrong temperatures reported for Core2Duo CPU in

[lmsensorslist]

Hi Jean,

Thanks for your reply.

On 03/10/2010 10:07 AM, Jean Delvare wrote:
>
> The value is reported by the CPU itself. The coretemp kernel driver is
> just passing it through. While the value is reported relative to the
> critical limit, and we have had this critical limit wrong for some
> models in the past, this is irrelevant here: the fact is that your CPU

Can you explain this a bit more?  You say coretemp is just passing it
through, which to me implies no calculation nor conversion of any kind. 
But that's not really the case, is it?  The CPU doesn't literally say "79"
to mean "79 degress Celsius" right?

> runs over its high limit when loaded. I've never seen any Intel Core2
> CPU reaching such a high temperature. This can mean only 2 things:
> * You happen to have a CPU with defective thermal sensors. The fact
>   that both cores agree makes me skeptical, but then again, as I have
>   no idea how the internal sensors could go wrong, it might as well
>   happen to both sensors at once.
> * Your heatsink and fan are not doing their job properly. This is my
>   favorite theory at this point.

It's certainly possible that I've messed that up somehow.  However, I've
installed many dozens of CPUs and heatsinks as a system builder over the
years, including 2 different ones in this particular system -- and,
there's basically nothing to it with Socket 775: you just sit the heatsink
on the CPU and push down the 4 pins.  I'm using the pre-applied thermal
compound on the Rosewill heatsink, but with the Intel heatsink that I was
originally using, I used Arctic Silver.  In both cases these high
temperatures were present.

> I would not be surprised that the CPU survives 3.5 years at these
> temperatures. You are still below the critical limit.

So regularly running in the 80-90 degree Celsius range won't necessarily
damage the chip?  I see what you mean that it's below the critical limit
of 100C, but it still seems like 80-90C might hurt it too.

> Hard disk drive temperature is a totally different thing. Assuming
> there is some space between the CPU and the HDD (and there always is on
> a desktop board) there is no reason for these temperature to match.

I know they are totally separate sensors, I just wanted to point out that
for example it's not the case that the whole PC is running hot, or just in
a really hot room, etc.  It's just these numbers for the CPU cores that
are high.

> The QST SDK might let us provide support for motherboard sensors, but
> this will not change the values reported by the coretemp driver. Best
> you can hope is extra temperature sensors for comparison purpose.

I'm hoping for that along with maybe fan RPM readouts, and ideally being
able to control the fan RPMs.

> What you can do is check the temperatures reported by the BIOS. It's
> difficult to know where the BIOS gets the values from, though...

OK, I just tested this, by running the "stress" command for a few minutes,
until the coretemp values were 91C and 92C.  I then immediately shut down
and went into the BIOS.  Here's the BIOS numbers:

68C CPU Die/Package Temperature
54C Motherboard Temperature
44C Motherboard Temperature
82C ICH Temperature
58C MCH Temperature

And here's the same BIOS numbers after sitting there in the BIOS for 10
minutes:

63C CPU Die/Package Temperature
50C Motherboard Temperature
44C Motherboard Temperature
83C ICH Temperature
54C MCH Temperature

I guess the die temp is the one that corresponds to the CPU?  But why
wouldn't it just show the 2 core temps?

Do you think it's possible that it really dissipated 20+ degrees during
the ~1 minute it took me to shut down and get into the BIOS?

> Fan control is not possible with only the coretemp driver, sorry. You
> might look in the BIOS options for an automatic fan speed control
> option, but given how hot your CPU already is, I wouldn't dare enabling
> it.

It's already set that way.  The CPU fan is silent when I first boot the
PC, and the idle core temp is ~75C.  But as soon as I do anything, the fan
kicks on quietly; then after 10-20 minutes of uptime and regular work,
it's running at or near full throttle.

Thanks,

--
Anthony DiSante
http://nodivisions.com/



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Re: [lm-sensors] Wrong temperatures reported for Core2Duo CPU in

[Jean Delvare]

On Wed, 10 Mar 2010 08:41:52 -0800, lmsensorslist@nodivisions.com wrote:
> Thanks for your reply.
> 
> On 03/10/2010 10:07 AM, Jean Delvare wrote:
> >
> > The value is reported by the CPU itself. The coretemp kernel driver is
> > just passing it through. While the value is reported relative to the
> > critical limit, and we have had this critical limit wrong for some
> > models in the past, this is irrelevant here: the fact is that your CPU
> 
> Can you explain this a bit more?  You say coretemp is just passing it
> through, which to me implies no calculation nor conversion of any kind. 
> But that's not really the case, is it?  The CPU doesn't literally say "79"
> to mean "79 degress Celsius" right?

You're right, it doesn't say 79. It says 21, meaning "21 degrees
Celsius below the critical temperature limit". As we assume this limit
to be 100°C for your CPU model, we end up with 79°C.

> > runs over its high limit when loaded. I've never seen any Intel Core2
> > CPU reaching such a high temperature. This can mean only 2 things:
> > * You happen to have a CPU with defective thermal sensors. The fact
> >   that both cores agree makes me skeptical, but then again, as I have
> >   no idea how the internal sensors could go wrong, it might as well
> >   happen to both sensors at once.
> > * Your heatsink and fan are not doing their job properly. This is my
> >   favorite theory at this point.
> 
> It's certainly possible that I've messed that up somehow.  However, I've
> installed many dozens of CPUs and heatsinks as a system builder over the
> years, including 2 different ones in this particular system -- and,
> there's basically nothing to it with Socket 775: you just sit the heatsink
> on the CPU and push down the 4 pins.  I'm using the pre-applied thermal
> compound on the Rosewill heatsink, but with the Intel heatsink that I was
> originally using, I used Arctic Silver.  In both cases these high
> temperatures were present.
> 
> > I would not be surprised that the CPU survives 3.5 years at these
> > temperatures. You are still below the critical limit.
> 
> So regularly running in the 80-90 degree Celsius range won't necessarily
> damage the chip?  I see what you mean that it's below the critical limit
> of 100C, but it still seems like 80-90C might hurt it too.

Well, that's pretty high, yes. I wouldn't like it for my own machine.
And probably your CPU won't live 15 years at this temperature. And if
your fan breaks, your machine will die immediately. But... again, as
long as you're below the critical limit, it should be mostly OK.

> > Hard disk drive temperature is a totally different thing. Assuming
> > there is some space between the CPU and the HDD (and there always is on
> > a desktop board) there is no reason for these temperature to match.
> 
> I know they are totally separate sensors, I just wanted to point out that
> for example it's not the case that the whole PC is running hot, or just in
> a really hot room, etc.  It's just these numbers for the CPU cores that
> are high.
> 
> > The QST SDK might let us provide support for motherboard sensors, but
> > this will not change the values reported by the coretemp driver. Best
> > you can hope is extra temperature sensors for comparison purpose.
> 
> I'm hoping for that along with maybe fan RPM readouts, and ideally being
> able to control the fan RPMs.
> 
> > What you can do is check the temperatures reported by the BIOS. It's
> > difficult to know where the BIOS gets the values from, though...
> 
> OK, I just tested this, by running the "stress" command for a few minutes,
> until the coretemp values were 91C and 92C.  I then immediately shut down
> and went into the BIOS.  Here's the BIOS numbers:
> 
> 68C CPU Die/Package Temperature
> 54C Motherboard Temperature
> 44C Motherboard Temperature
> 82C ICH Temperature
> 58C MCH Temperature
> 
> And here's the same BIOS numbers after sitting there in the BIOS for 10
> minutes:
> 
> 63C CPU Die/Package Temperature
> 50C Motherboard Temperature
> 44C Motherboard Temperature
> 83C ICH Temperature
> 54C MCH Temperature
> 
> I guess the die temp is the one that corresponds to the CPU?

Yes, it probably comes from the CPU internal sensors, although only
disassembling the BIOS could tell for sure.

> But why wouldn't it just show the 2 core temps?

Probably because it would need extra code and the author decided
wasn't worth it. The BIOS code doesn't need to be multi-core-aware.
There's little point in monitoring the temperature of a core you're not
even using.

> Do you think it's possible that it really dissipated 20+ degrees during
> the ~1 minute it took me to shut down and get into the BIOS?

It's not impossible. Especially as you said that the heatsink wasn't
that hot to the touch despite the high temperature value, this suggests
that your heatsink and fan are able to extract the extra temperature.

I admit it's a bit of a paradox though, as my first guess was that the
heatsink and fan was insufficient. Maybe you just happen to have a CPU
mode which heats a lot.

You might get a better view by comparing Linux idle with BIOS idle.
Some BIOS are in a tight loop so they are better compared to a
moderately loaded Linux, but the numbers above suggest this isn't your
case (the CPU temperature in the BIOS was decreasing over time.)

Again, one possibility is that we got the critical temperature limit
wrong for your CPU and it is lower than the driver thinks. But that
doesn't change the fact that you're running 21 degrees below the limit,
which is the smaller merging I've ever seen for this CPU model.

> > Fan control is not possible with only the coretemp driver, sorry. You
> > might look in the BIOS options for an automatic fan speed control
> > option, but given how hot your CPU already is, I wouldn't dare enabling
> > it.
> 
> It's already set that way.  The CPU fan is silent when I first boot the
> PC, and the idle core temp is ~75C.  But as soon as I do anything, the fan
> kicks on quietly; then after 10-20 minutes of uptime and regular work,
> it's running at or near full throttle.

Not surprising, given the temperature values you're shown.

-- 
Jean Delvare
http://khali.linux-fr.org/wishlist.html

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Re: [lm-sensors] Wrong temperatures reported for Core2Duo CPU in

[lmsensorslist]

Today I installed Windows XP on this same system, to see what it would
report for the core temperatures.  I installed 3 apps for this: SpeedFan,
Core Temp, and Real Temp.  Here's what they reported while idle and after
10 minutes of high load (all 3 temperature apps reporting simultaneously):

SpeedFan: idle 49C, loaded 70C
Core Temp: idle 54C, loaded 75C
Real Temp: idle 59C, loaded 80C

The Core Temp & Real Temp apps explicitly show what they're using for
TjMax: 85C and 90C respectively.  And from the idle/load temps it looks
like SpeedFan is probably using 80C.  lm-sensors/coretemp are 10 degrees
higher still.

So which is correct?  Is the TjMax value published by Intel, and/or
definitively known to be a certain value?  I searched intel.com and the
datasheet for my CPU (the E6600) but didn't see it.  And this tomshardware
piece seems to say that Intel deliberately obfuscates this information
(read the update at the bottom):

http://www.tomshardware.com/news/intel-dts-specs,6517.html

If SpeedFan is correct, I feel much better about my CPU; but if
lm-sensors/coretemp is right, I'm more worried.

Thanks,

--
Anthony DiSante
http://nodivisions.com/



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Re: [lm-sensors] Wrong temperatures reported for Core2Duo CPU in

[lmsensorslist]

> Today I installed Windows XP on this same system, to see what it would
> report for the core temperatures.  I installed 3 apps for this: SpeedFan,
> Core Temp, and Real Temp.  Here's what they reported while idle and after
> 10 minutes of high load (all 3 temperature apps reporting simultaneously):
>
> SpeedFan: idle 49C, loaded 70C
> Core Temp: idle 54C, loaded 75C
> Real Temp: idle 59C, loaded 80C
>
> The Core Temp & Real Temp apps explicitly show what they're using for
> TjMax: 85C and 90C respectively.  And from the idle/load temps it looks
> like SpeedFan is probably using 80C.  lm-sensors/coretemp are 10 degrees
> higher still.
>
> So which is correct?  Is the TjMax value published by Intel, and/or
> definitively known to be a certain value?  I searched intel.com and the
> datasheet for my CPU (the E6600) but didn't see it.  And this tomshardware
> piece seems to say that Intel deliberately obfuscates this information
> (read the update at the bottom):
>
> http://www.tomshardware.com/news/intel-dts-specs,6517.html
>
> If SpeedFan is correct, I feel much better about my CPU; but if
> lm-sensors/coretemp is right, I'm more worried.


Sorry for the double-post, but I meant to re-iterate just for
completeness' sake: the idle/loaded temps reported by lm-sensors+coretemp
under Linux are ~73C/93C, in contrast to the lower temperatures reported
by the 3 Windows apps mentioned above.

Thanks,

--
Anthony DiSante
http://nodivisions.com/



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Re: [lm-sensors] Wrong temperatures reported for Core2Duo CPU in

[Luca Tettamanti]

On Wed, Mar 10, 2010 at 7:10 PM, Jean Delvare <khali@linux-fr.org> wrote:
> On Wed, 10 Mar 2010 08:41:52 -0800, lmsensorslist@nodivisions.com wrote:
>> OK, I just tested this, by running the "stress" command for a few minutes,
>> until the coretemp values were 91C and 92C.  I then immediately shut down
>> and went into the BIOS.  Here's the BIOS numbers:
>>
>> 68C CPU Die/Package Temperature
>> 54C Motherboard Temperature
>> 44C Motherboard Temperature
>> 82C ICH Temperature
>> 58C MCH Temperature
>>
>> And here's the same BIOS numbers after sitting there in the BIOS for 10
>> minutes:
>>
>> 63C CPU Die/Package Temperature
>> 50C Motherboard Temperature
>> 44C Motherboard Temperature
>> 83C ICH Temperature
>> 54C MCH Temperature
>>
>> I guess the die temp is the one that corresponds to the CPU?
>
> Yes, it probably comes from the CPU internal sensors, although only
> disassembling the BIOS could tell for sure.

From my experience on Asus boards the "CPU" temperature shown in the
BIOS is usually read from the external monitoring chip, and only
rarely from the CPU itself (using PECI - with a totally wrong tjmax -
sigh).
The ICH temperature is also suspiciously high.

Luca

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Re: [lm-sensors] Wrong temperatures reported for Core2Duo CPU in

[Jean Delvare]

Hi Anthony,

On Thu, 11 Mar 2010 12:38:05 -0800, lmsensorslist@nodivisions.com wrote:
> > Today I installed Windows XP on this same system, to see what it would
> > report for the core temperatures.  I installed 3 apps for this: SpeedFan,
> > Core Temp, and Real Temp.  Here's what they reported while idle and after
> > 10 minutes of high load (all 3 temperature apps reporting simultaneously):
> >
> > SpeedFan: idle 49C, loaded 70C
> > Core Temp: idle 54C, loaded 75C
> > Real Temp: idle 59C, loaded 80C
> >
> > The Core Temp & Real Temp apps explicitly show what they're using for
> > TjMax: 85C and 90C respectively.  And from the idle/load temps it looks
> > like SpeedFan is probably using 80C.  lm-sensors/coretemp are 10 degrees
> > higher still.

Very interesting that apparently nobody agrees on what TjMax is.

> > So which is correct?  Is the TjMax value published by Intel, and/or
> > definitively known to be a certain value?  I searched intel.com and the
> > datasheet for my CPU (the E6600) but didn't see it.  And this tomshardware
> > piece seems to say that Intel deliberately obfuscates this information
> > (read the update at the bottom):
> >
> > http://www.tomshardware.com/news/intel-dts-specs,6517.html

This is our experience as well, we asked Intel repeatedly about the
TjMax values for various CPU models but couldn't get a clear answer.

> > If SpeedFan is correct, I feel much better about my CPU; but if
> > lm-sensors/coretemp is right, I'm more worried.

Unfortunately you will probably never know. The only reliable data point
here is the difference between the operating point and TjMax, not the
absolute temperature values.

> Sorry for the double-post, but I meant to re-iterate just for
> completeness' sake: the idle/loaded temps reported by lm-sensors+coretemp
> under Linux are ~73C/93C, in contrast to the lower temperatures reported
> by the 3 Windows apps mentioned above.

Thinking in relative terms, your system is running under Windows at -31
idle and -10 under heavy load; Linux at -27 idle and -7 under heavy
load. So the bottom line is that your system runs hotter in Linux than
Windows. You should check if you have services running that suck your
CPU, or, if you self-built your kernel, if you missed some CPU-related
options such as CONFIG_CPU_IDLE, ACPI, etc. And also make sure you have
the acpi_cpufreq and cpufreq_conservative drivers loaded and used. The
"powertop" utility might come in handy to track such issues.

The 20째C difference between idle and heavy load seems reasonable, my own
mobile Core Duo CPU has an even larger difference (37째C!). The 7째C
margin is more problematic, but that being said, I just checked mine
and it's running only 12째C below the limit under heavy load... That's
not so different from yours. So maybe these CPUs really run hot and so
be it.

-- 
Jean Delvare
http://khali.linux-fr.org/wishlist.html

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Re: [lm-sensors] Wrong temperatures reported for Core2Duo CPU in

[Jean Delvare]

On Fri, 12 Mar 2010 10:40:48 +0100, Luca Tettamanti wrote:
> On Wed, Mar 10, 2010 at 7:10 PM, Jean Delvare <khali@linux-fr.org> wrote:
> > On Wed, 10 Mar 2010 08:41:52 -0800, lmsensorslist@nodivisions.com wrote:
> >> OK, I just tested this, by running the "stress" command for a few minutes,
> >> until the coretemp values were 91C and 92C.  I then immediately shut down
> >> and went into the BIOS.  Here's the BIOS numbers:
> >>
> >> 68C CPU Die/Package Temperature
> >> 54C Motherboard Temperature
> >> 44C Motherboard Temperature
> >> 82C ICH Temperature
> >> 58C MCH Temperature
> >>
> >> And here's the same BIOS numbers after sitting there in the BIOS for 10
> >> minutes:
> >>
> >> 63C CPU Die/Package Temperature
> >> 50C Motherboard Temperature
> >> 44C Motherboard Temperature
> >> 83C ICH Temperature
> >> 54C MCH Temperature
> >>
> >> I guess the die temp is the one that corresponds to the CPU?
> >
> > Yes, it probably comes from the CPU internal sensors, although only
> > disassembling the BIOS could tell for sure.
> 
> From my experience on Asus boards the "CPU" temperature shown in the
> BIOS is usually read from the external monitoring chip, and only
> rarely from the CPU itself (using PECI - with a totally wrong tjmax -
> sigh).

Yes, but this is an Intel board here, with the QST thing, so I wouldn't
rely on the usual assumptions.

> The ICH temperature is also suspiciously high.

Indeed.

-- 
Jean Delvare

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Re: [lm-sensors] Wrong temperatures reported for Core2Duo CPU in

[Hubert Kario]

On Friday 12 March 2010 10:40:48 Luca Tettamanti wrote:
> On Wed, Mar 10, 2010 at 7:10 PM, Jean Delvare <khali@linux-fr.org> wrote:
> > On Wed, 10 Mar 2010 08:41:52 -0800, lmsensorslist@nodivisions.com wrote:
> >> OK, I just tested this, by running the "stress" command for a few
> >> minutes, until the coretemp values were 91C and 92C.  I then
> >> immediately shut down and went into the BIOS.  Here's the BIOS numbers:
> >> 
> >> 68C CPU Die/Package Temperature
> >> 54C Motherboard Temperature
> >> 44C Motherboard Temperature
> >> 82C ICH Temperature
> >> 58C MCH Temperature
> >> 
> >> And here's the same BIOS numbers after sitting there in the BIOS for 10
> >> minutes:
> >> 
> >> 63C CPU Die/Package Temperature
> >> 50C Motherboard Temperature
> >> 44C Motherboard Temperature
> >> 83C ICH Temperature
> >> 54C MCH Temperature
> >> 
> >> I guess the die temp is the one that corresponds to the CPU?
> > 
> > Yes, it probably comes from the CPU internal sensors, although only
> > disassembling the BIOS could tell for sure.
> 
> From my experience on Asus boards the "CPU" temperature shown in the
> BIOS is usually read from the external monitoring chip, and only
> rarely from the CPU itself (using PECI - with a totally wrong tjmax -
> sigh).
> The ICH temperature is also suspiciously high.

There are three sensors in C2D processors - two T junction, and one Tcase

Tcase is read by mainboard, the die has only the sensor, as it was since the 
days of PIII if I recall right
Tjunction are read using internal CPU circuits.

Some programs use the Tj and some use Tcase as the value for "CPU temp".

The usual location for Tcase is between the cores, on top of the silicon die, 
Tjunction reside in ALU, theoretically in the place that can become the 
hottest under load.

With good heat spreader and correctly applied thermal paste the difference 
between them shouldn't differ by more than 1-3C idle and 3-5C on load. If it 
does, the heat spreader isn't placed corretly or there are air bubbles in the 
paste.
But more commonly it means that the sensors aren't calibrated properly.

The correct temperatures for C2D and C2Q chips at idle (with all power saving 
features ON) are about 4-5C above ambient for Tcase and 6-7C above ambient for 
TJunction.

Look on overclocking forums for more information, they usually dig the deepest 
for such info :)
-- 
Hubert Kario
QBS - Quality Business Software
ul. Ksawerów 30/85
02-656 Warszawa
POLAND
tel. +48 (22) 646-61-51, 646-74-24
fax +48 (22) 646-61-50

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Re: [lm-sensors] Wrong temperatures reported for Core2Duo CPU in

[lmsensorslist]

>> Sorry for the double-post, but I meant to re-iterate just
>> for completeness' sake: the idle/loaded temps reported by
>> lm-sensors+coretemp under Linux are ~73C/93C, in contrast
>> to the lower temperatures reported by the 3 Windows apps
>> mentioned above.
>
> Thinking in relative terms, your system is running under Windows at -31
> idle and -10 under heavy load; Linux at -27 idle and -7 under heavy
> load. So the bottom line is that your system runs hotter in Linux than
> Windows. You should check if you have services running that suck your
> CPU, or, if you self-built your kernel, if you missed some CPU-related
> options such as CONFIG_CPU_IDLE, ACPI, etc. And also make sure you have
> the acpi_cpufreq and cpufreq_conservative drivers loaded and used. The
> "powertop" utility might come in handy to track such issues.
>
> The 20°C difference between idle and heavy load seems reasonable, my own
> mobile Core Duo CPU has an even larger difference (37°C!). The 7°C
> margin is more problematic, but that being said, I just checked mine
> and it's running only 12°C below the limit under heavy load... That's
> not so different from yours. So maybe these CPUs really run hot and so
> be it.

That makes sense.  And yeah, I do generally have tons of stuff running
under Linux, so the system doesn't spend much time being entirely idle.

Well I've just upgraded my PC's case to this one:

http://www.newegg.com/Product/Product.aspx?Item=N82E16811233049

It's nothing super fancy, but it does have one of those side-vents with a
duct going straight to the CPU, and it also has a 120mm rear exhaust fan
(plus a spot in the front for an intake fan).  My old case was a nice,
solid In-Win case, but it was about 10 years old, and had no case fans at
all -- not even spots for them -- and the CPU's fan was almost right
against the side of the PSU.  So cooling in there was pretty suboptimal.

This new case is a huge improvement: my CPU is idling around 63-65C now,
compared to 73-75C in the old case.  Under load it goes as high as the
mid-80s, not into the 90s as in the old case.

I'd like it to be even cooler, and will probably get a front intake fan
next, but I'm really happy with this upgrade, especially because it's
solved my main complaint: the fan noise.  It's super quiet now because the
CPU fan and rear case fan are spinning pretty slowly, and only rarely
speed up -- as opposed to the CPU fan being obnoxious nearly 24/7 in the
old case.

--
Anthony DiSante
http://nodivisions.com/



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Re: [lm-sensors] Wrong temperatures reported for Core2Duo CPU in

[Jean Delvare]

On Sun, 14 Mar 2010 07:41:16 -0700, lmsensorslist@nodivisions.com wrote:
> That makes sense.  And yeah, I do generally have tons of stuff running
> under Linux, so the system doesn't spend much time being entirely idle.
> 
> Well I've just upgraded my PC's case to this one:
> 
> http://www.newegg.com/Product/Product.aspx?Item=N82E16811233049
> 
> It's nothing super fancy, but it does have one of those side-vents with a
> duct going straight to the CPU, and it also has a 120mm rear exhaust fan
> (plus a spot in the front for an intake fan).  My old case was a nice,
> solid In-Win case, but it was about 10 years old, and had no case fans at
> all -- not even spots for them -- and the CPU's fan was almost right
> against the side of the PSU.  So cooling in there was pretty suboptimal.
> 
> This new case is a huge improvement: my CPU is idling around 63-65C now,
> compared to 73-75C in the old case.  Under load it goes as high as the
> mid-80s, not into the 90s as in the old case.
> 
> I'd like it to be even cooler, and will probably get a front intake fan
> next, but I'm really happy with this upgrade, especially because it's
> solved my main complaint: the fan noise.  It's super quiet now because the
> CPU fan and rear case fan are spinning pretty slowly, and only rarely
> speed up -- as opposed to the CPU fan being obnoxious nearly 24/7 in the
> old case.

Hey, glad to hear that you finally solved your problem :)

-- 
Jean Delvare

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