Level 1

0 points

Mac Pro Temperature question

I am trying to find out what the max Temperature the cpu's and ram should reach when operating in normal Temperature conditions ( in my case 3Ghz cpu's) I frequently get my cores running at %100 and am concered that they will over heat. I am using Temperature Monitor 4.0

MacPro 3.00Ghz 23"ACD ATIx1900, Mac OS X (10.4.8)

Posted on Nov 15, 2006 2:41 AM

60 replies

dotnet

Level 1

120 points

Nov 20, 2006 3:24 AM in response to Tesselator

Broken iMac actually did line the streets in
neighborhoods all across Japan. But Apple techs will tell you the
same thing about damaged iMacs from over-heating.

It could well be that that model was a dud design, I have no idea. But we're talking about the Mac Pro, and you don't see them lining the streets, dead from overheating.

Really? What is that illustration on page 82 of that PDF
you linked? That doesn't show a sensor in or on the IHS?

There a no sensors in that diagram, but it shows how silicon, heat spreader and heat sink relate to each other.

But you're already losing me here. First you say "it is
well defined as the temperature at the center of the
heat spreader [IHS]" and now you're saying "We haven't got
sensors at the heat spreader [IHS]"

That's the conundrum. We're trying to judge how well a design specification at the heat spreader is met, but only have sensors in the silicon and heat sink.

we can extrapolate

We can? How?

Using a simple approximate description of thermal flow: thermal resistance equals temperature drop divided by heat dissipation ("Ohm's law" of thermal flow).

Let's call the thermal resistance between die and heat spreader R, and the max allowable on-die temperature X. Assuming that R and X are the same for both the 5150 and the 5160 we have:

R = (X - 65°C)/65W = (X - 56.5°C)/85W

It follows that X is 92.6°C.

Where's my quadratic equation calculator? 😀 But 90
is absolutly NOT what I would expect! That's almost 200F
for a proc that is supposedly supposed to have an
exremely low thermal profile.

Is it? I'd only expect that in mobile chips (Merom etc).

IIRC, an Athlon system I once owned had a CPU temperature warning threshold set in the BIOS of about 80°C, and a shutdown threshold of 95°C.

The "CPU Temp" as told by "Fan Speed Version 4.28" for my 3400+ AMD
is only 100F. 120F (49c) at extended peroids of 100% operation.
At ~130F (55c) it loses it's brains and the system crashes.

Sounds like a faulty chip.

The Pentium D dual core CPUs have a thermal design power of 130W and
a maximum operating temperature of less than 70°C. You're
saying that the Xeon is supposed to run TWICE as hot as an 3400+
and the system fans in a MacPro are supposed to be
running at ONE TENTH the speed as a typical PC case?

Dunno, but a few things come to mind: A lot of PCs don't have case fans, just one on the power supply and one on the CPU. Some have one small (8cm) case fan. CPU fans are typically tiny and have to run at much faster speeds than the giant Mac Pro fans, in order to move the same amount of air. Typical PC cases have badly design air flows. At 130W TDP the temperature difference between die and ambient is much higher, unless you reduce the thermal resistance (e.g. by running fans at dremel speed).

Well, yes, actualy there is. The drives are running
too hot as well.

Oh dear, that one again. The disks are running well within manufacturer specs.

Hehe, but that document said that the staged cooling
profile was optional and not recomended. Or at least
that's how I read it.

There are profiles to choose from, but the built-in temperature management will not allow the silicon to overheat.

Hatter said it right. Cool is good.

True, but quiet is good, too. In the long run, my personal work comfort and low stress levels are much more valuable to me than a piece of hardware.

That said, I only ever managed to push the core temps over 60°C once: by running 4 instances of dc doing some silly calculation (9^1234567) in a loop. During normal operation they stay well under 50°C. Right now they're under 40°C.

Cheers
Steffen.

Trau Author

Level 1

0 points

Nov 20, 2006 8:27 AM in response to Hworld

How did you adjust the fan speed manualy?

Trau Author

Level 1

0 points

Nov 20, 2006 8:48 AM in response to dotnet

Here is an e-mail and reply I recieved regarding this issue from the head developer of Temperature and Hardware Monitor Dr. Marcel Bresink.

Thank you very much for your interest in Temperature Monitor and
your technical questions regarding Mac Pro hardware.

Am 19.11.2006 um 20:13 schrieb CGI-Mailer:
There is a thread in apple discussions regarding what the max core temps should reach on the xeon procs on the Mac Pro. I am very confused and need to be sure that I am not burning my procs out. Could you please take a look at the thread and comment to me via e-mail or in the thread directly?

http://discussions.apple.com/thread.jspa?threadID=734247&tstart=0

I have to say that there are many false claims and assumptions
in this thread, even the response from Intel(R) Technical Support
is misleading, although it is technically correct. It would be very
lengthy to discuss this all in detail, so let me mention just the
most important facts:

- When speaking about temperature specifications it is important to
note that all limits can be applied to specific sensor locations
and specific measurement methods only. So it does not make sense to
speak about a "maximum operating temperature for processor X", you'll
have to specify the "maximum operating temperature for the sensor
location A when monitoring processor X under condition B".

- Intel Xeon 5100 processors use a variety of internal and external
temperature sensors, and several different monitoring technologies:

1) The processor case temperature is monitored by an internal
temperature diode and the so-called "Thermal Control Circuit" (TCC).
There are two different mechanisms called "Thermal Monitor" (TM) and
"Thermal Monitor 2" (TM2) that allow the CPU to check and control its own
temperature. This technology is considered to be outdated for the Xeon 5100
although it is still built in to maintain compatibility with older system
designs. Temperature Monitor 4.0 does NOT display this sensor on the Mac Pro.

2) Each core of each CPU is monitored by several internal temperature
sensors that are placed at critical points on the chip-die. These sensors
are called "Digital Thermal Sensors" (DTS). Their values are automatically
averaged and smoothed, reflecting high-precision readings for the situation
at the cores themselves. The DT Sensors are displayed as "CPU Core" sensors
by Temperature Monitor. They represent the recommended technology to monitor
current Xeon 5100 processors.

3) There are external sensors, measuring the temperature at the processor
heat sinks under specifications defined by the manufacturer, in this case Apple.
These sensors are reflecting the processor package and airflow temperatures. They
are being displayed as "CPU Heat Sink" sensors by Temperature Monitor.

- The maximum operating temperature mentioned by the Intel Tech representative
is based on a special measurement method defined by the "Dual-Core Intel Xeon
Processors 5100 Series Thermal/Mechanical Design Guidelines"
( http://www.intel.com/design/xeon/guides/313357.htm ). The readings basically
reflect a "TCC-like" approach, not the DTS technology. DTS values are expected
to be much higher than the values measured at the outer CPU package.

- It is correct that Intel did not and will not officially publish absolute
temperature limits for the "on core" DTS sensors of the Xeon 5100. However,
based on a series of tests run with Apple Mac Pro systems, it can be assumed
that the maximum allowed DTS temperature for which Intel and Apple designed the
Mac Pro is 85°C. (To put this in relation, it should be noted that the maximum
DTS temperature for Intel Core processors under normal operating conditions
is 100°C and the so-called "catastrophic" limit is at 125°C. For more
information, see the official data sheets at http://www.intel.com/design/mobile/datashts/309221.htm . Of course the Intel
Core series should not directly be compared to the 5100 series.)

- Temperature Monitor displays the maximum sensor limits in the third column
of the window "Sensor Overview". The application makes sure to only display
limits for sensor locations where the specifications are known. The values either
come from official documentation of Apple, or internal tables built into Mac OS X,
or tables built into the firmware of the system, depending on what Macintosh
model and what sensor location is being monitored.

- Even if somebody should assume that the maximum limit of 85°C for the
Xeon 5100 DTS core sensors were incorrect, the basic statement of Temperature
Monitor that the "displayed reading for core X is Y degrees below the displayed
limit" would still be correct. That's because the DTS technology computes
the current temperature as difference to the upper limit, not as absolute
temperature. The core will be overheating only if the current value approaches
the limit. It doesn't really matter what the exact limit is for monitoring
purposes at that particular sensor.

- All up-to-date Intel processors simply cannot overheat. As mentioned, they
use several different technologies to monitor themselves and will take immediate
action automatically if the temperatures reach a critical condition. The CPUs will
"throttle down" either by reducing their clock frequencies, or by repeatedly
switching to periods of inactivity for some microseconds. These protection
mechanisms work independently of operating system and mainboard.

- The Mac Pro uses four different fans. Each fan is controlled individually,
using the temperature information in different thermal zones. Some third-party
applications to manipulate the minimum fan speeds may give you the wrong
impression that fan speeds are controlled by CPU temperature only.

- Each FB-DIMM contains its own controller, called "Advanced Memory Buffer (AMB)".
Each AMB also contains its own temperature sensor. The maximum temperature
of an FB-DIMM, measured by the AMB, lies in the interval between 95 and 125°C
(it will vary from manufacturer to manufacturer), the typical value is 110°C.
So all memory-related readings mentioned in the thread should be considered low
and well within specs.

I hope this information is helpful to you. If I can be of further assistance,
don't hesitate to contact me.

Best regards,
Marcel Bresink

davepk

Level 1

20 points

Nov 20, 2006 2:55 PM in response to Hworld

Hi Hworld,

I created a modified version of fan control that you, and others, might be interested.

http://forums.macrumors.com/showthread.php?t=253965

dotnet

Level 1

120 points

Nov 20, 2006 3:04 PM in response to Trau

Thanks for sharing this Trau, this is very interesting.

Curiously, there appears to be a case temperature sensor, we just can't read it (at least not with TemperatureMonitor)...

Cheers
Steffen.

Trau Author

Level 1

0 points

Nov 20, 2006 7:10 PM in response to dotnet

It looks as if your calculations in your last post were in the ballpark!

Nov 20, 2006 8:09 PM in response to davepk

Hi Hworld,

I created a modified version of fan control that you,
and others, might be interested.

http://forums.macrumors.com/showthread.php?t=253965

Hi,

Mac dev-newb here 😉

I DL your code and try to build it and I ger two errors.
Looking at the errors it says the MacOSX10.4u.sdk does
not exist. Searching online ( http://developer.apple.com/sdk/ )
and elsewhere reveals nothing that I can recognize.

Where? How?
Thanks!

davepk

Level 1

20 points

Nov 20, 2006 8:47 PM in response to Tesselator

lol,

I'm a Mac Dev Newb as well... Took me awhile just to figure out how to make changes to the 3 sliders on the pref panel.

Not sure what your errors are but maybe they are due to missing SDKs? I know this code needs the IOKit sdk. Maybe it was an optional install component when you installed XCode? Or only comes as part of the ADC XCode distribution?

You might need to join ADC to gain access to the proper SDKs...
Membership is free at http://connect.apple.com give it a try.

MP Mac OS X (10.4.7)

Nov 20, 2006 9:30 PM in response to dotnet

Broken iMac actually did line the streets in
neighborhoods all across Japan. But Apple techs
will tell you the
same thing about damaged iMacs from over-heating.

It could well be that that model was a dud design, I
have no idea. But we're talking about the Mac Pro,
and you don't see them lining the streets, dead from
overheating.

You left out the word "Yet" !!! Muahahaaa... 😀

Really? What is that illustration on page 82 of that PDF
you linked? That doesn't show a sensor in or on the IHS?

There a no sensors in that diagram, but it shows how
silicon, heat spreader and heat sink relate to each
other.

It says... Oh yeah, I misread it. OK.

But you're already losing me here. First you say "it is
well defined as the temperature at the center of the
heat spreader [IHS]" and now you're saying "We haven't got
sensors at the heat spreader [IHS]"

That's the conundrum. We're trying to judge how well
a design specification at the heat spreader is met,
but only have sensors in the silicon and heat sink.

Well, we don't even know that much actually.

we can extrapolate

We can? How?

Using a simple approximate description of thermal
flow: thermal resistance equals temperature drop
divided by heat dissipation ("Ohm's law" of thermal
flow).

Thanks. CS at UCI for me was 24 years ago. 😉 Been doing
and teaching art (3D CG) for the past 9 years.

Let's call the thermal resistance between die and
heat spreader R, and the max allowable on-die
temperature X. Assuming that R and X are the same for
both the 5150 and the 5160 we have:

R = (X - 65°C)/65W = (X - 56.5°C)/85W

It follows that X is 92.6°C.

where's my quadratic equation calculator? 😀 But 90
is absolutly NOT what I would expect! That's almost 200F
for a proc that is supposedly supposed to have an
exremely low thermal profile.

Is it? I'd only expect that in mobile chips (Merom
etc).

Hmm, well I thought so at least. I have heard lots of rumors
printed up in tech journals and flowing out from test-bench
sites that proclaim that they know such a thing was one of
the main goals at Intel for the 5100 series. Most of them
conclude that Intel indeed had good success in that area. <shrug>

IIRC, an Athlon system I once owned had a CPU
temperature warning threshold set in the BIOS of
about 80°C, and a shutdown threshold of 95°C.

The "CPU Temp" as told by "Fan Speed Version 4.28" for my 3400+ AMD
is only 100F. 120F (49c) at extended peroids of 100% operation.
At ~130F (55c) it loses it's brains and the system crashes.

Sounds like a faulty chip.

No, that was just it's thermal limits. Maybe a different
batch had slightly different sensitivities but not by much
without revisions.

The Pentium D dual core CPUs have a thermal design power of 130W and
a maximum operating temperature of less than 70°C. You're
saying that the Xeon is supposed to run TWICE as hot as an 3400+
and the system fans in a MacPro are supposed to be
running at ONE TENTH the speed as a typical PC case?

Dunno, but a few things come to mind: A lot of PCs
don't have case fans, just one on the power supply

Which acts as a case fan. :P

and one on the CPU. Some have one small (8cm) case
fan. CPU fans are typically tiny and have to run at
much faster speeds than the giant Mac Pro fans, in
order to move the same amount of air. Typical PC
cases have badly design air flows. At 130W TDP the
temperature difference between die and ambient is
much higher, unless you reduce the thermal resistance
(e.g. by running fans at dremel speed).

Well, yes, actualy there is. The drives are
running too hot as well.

Oh dear, that one again. The disks are running well
within manufacturer specs.

Nope! You're totally wrong and you are misleading others
by sayig so within an OTHERWISE intelligent discussion.

If you like your HardDrive you better NOT EVER EVER EVER let
it reach the manufacturer Max value. Running it even near
the max will reduce performance and DRASTICALLY decrease
it's lifespan. Target temp for almost all HDD units on
the market or in use today is 30c. I can't stress this
strongly enough! Niether can I state strongly enough how
dilluded and just plain dumb anyone would be to think
otherwise.

These are the facts coming out of every test site and research
lab there is that's worth anything. The ONLY relief offered
to these dilusional ones is today's very low drive prices.
Meaning that because you can get a 300gig for $50 you may
deside to just not give a flying leap.

That does NOT change the FACT that at 40c you are stressing
the unit about the same amount as if you were applying a full
time 100% workload on it.

But you may not care. If the logic elsewhere in this thread
is the prevailing theme: Hey, the manufacturer made i that
way.. So if it breaks it's thier fault.

LOL why not apply that same logic to you car! The speedometer
says 120! So when you get a ticket it's the manufacturers'
fault! Or rev it constantly at it's MAX rpm. Hey! It's
within the limits of the manufacturers spec... Do it!

Grr... :P

Hehe, but that document said that the staged cooling
profile was optional and not recomended. Or at least
that's how I read it.

There are profiles to choose from, but the built-in
temperature management will not allow the silicon to
overheat.

kewl... Still it will allow it to reach life reducing stress
levels.

Xeons are usually pretty hardy though. They are the server
rated Intel parts so I suppose that even letting them run
on the hot side the whole time won't kill them before you
are needing or wanting a new machine. This is NOT true of
some of the other components in your MacPro however and
keeping the procs cool is just a natural part of total
system cooling. So...

Hatter said it right. Cool is good.

True, but quiet is good, too. In the long run, my
personal work comfort and low stress levels are much
more valuable to me than a piece of hardware.

Well the fans are still virtually SILENT at anything under
1500. There is like, no audable difference AT ALL by running
them at 1000~1200. At least not in my system. And I have
my office set up as a recording studio of sorts. I make
video tutorials and such. Here's one of them:

ftp://ftp.newtek.com/pub/LightWave/LW9/ShaderIntro_AVI.avi
You will need the Ensharpen codec to play the file:
http://www.techsmith.com/download/codecs.asp

So it's not just my ears that are monitoring the environment.
There are some world class condensor and dynamic mics in
front of me.

My current favorite:
http://www.heilsound.com/amateur/pr-40.htm
http://www.heilsound.com/amateur/Images/PR-40-SM-2-side-CBS_L.jpg

That said, I only ever managed to push the core temps
over 60°C once: by running 4 instances of dc doing
some silly calculation (9^1234567) in a loop. During
normal operation they stay well under 50°C. Right now
they're under 40°C.

Yeah, I'm amazed at how cool they run under low loads. They
are really sweet procs that's for sure! It's just a little
disheartening that Apple allows them to ramp up under load
conditions thereby introducing excess unwanted heat in to
the system. I'm still convinced that Apple blew chunks on
the fan thing. If not from the cpus, the proof comes from
the other components in the system. Otherwise - and even
so - MacPro is an AWESOME system!!! Espacailly considering
the price-tag!!! Man! I'm really happy with this thing!
Even moreso after installing Fan Control and a RAID. 😉

Nov 20, 2006 11:22 PM in response to davepk

I hope this information is helpful to you. If I can
be of further assistance, don't hesitate to contact
me.

Best regards,
Marcel Bresink

Mr. Marcel Bresink,

If you're reading this; thank you! Very informative and
professional! Lots of good stuff in there. When Apple
states that they sell the system with "Printed and disk
based documentation" this is the very kind of thing I
always hope will be included. It never is though and
guys like you make the world just a little better place
to live in. No really! I mean it!

Just for the sake of discussion however I do take slight
exception to one of your paragraphs however. 😀 hehe I bet
you knew this was coming. :P

- When speaking about temperature specifications it is
important to note that all limits can be applied to
specific sensor locations and specific measurement methods
only. So it does not make sense to speak about a "maximum
operating temperature for processor X", you'll have to
specify the "maximum operating temperature for the sensor
location A when monitoring processor X under condition B".

It really a matter of what is at hand. A user is presented
with a lable (a sensor lable) and a number (a temperature).
That's all we have to go on and really as long as everyone
is talking about the same lable (sensor) then saying such
things like "The max core temp for a 5150 is 120c just
before you will probably need to replace it and 90c is it's
recomended limit." or "If you core is at 90c your processor
is running too hot for the good of the system." and etc. is
just fine and ideally correct.

Also while you addressed "maximum" and "recomended maximum"
temperatures I wounder if you would also have the time or
inclination to address the topic of general PC health,
longevity, and how temperature in specific relates to that
topic. In relation, some target values for achieving optimal
proformance, and etc.

Thanks.

dotnet

Level 1

120 points

Nov 22, 2006 9:41 PM in response to Tesselator

Oh dear, that one again. The disks are running
well within manufacturer specs.

Nope! You're totally wrong and you are misleading others
by sayig so within an OTHERWISE intelligent discussion.

If you like your HardDrive you better NOT EVER EVER
EVER let it reach the manufacturer Max value. Running it
even near the max will reduce performance and DRASTICALLY
decrease it's lifespan. Target temp for almost all HDD
units on the market or in use today is 30c. I can't
stress this strongly enough! Niether can I state strongly
enough how dilluded and just plain dumb anyone would be to
think otherwise.

Including the hard drive vendor? I grant you that vendors can be thoroughly deluded, however, your frantic handwaving is so much less convincing to me than this (from Maxtor's KB):

Question / Symptom

Ambient air temperatures of 95°F (35°C) or greater and
poor ventilation from the smaller case designs of Shuttle
boxes, LAN party boxes, racks, cabinets, and drawers, can
shorten the life of your hard disk.

Answer

All Maxtor ATA, SATA, and SCSI drives can operate with or
without a fan, providing the hard disk temperature does
not exceed 131°F (55°C) as measured from the top cover of
the drive. Reliability will be compromised when the drive
is exposed to temperatures above 55°C or 131°F.

I'll choose to believe Maxtor until you can provide some factual backup for your assertion.

Cheers
Steffen.

Mac Pro 2.66GHz, 4GB RAM, X1900, 3x250GB MaxLine III, 750GB 7200.10, 2xSD, BT Mac OS X (10.4.8) 22" Philips 202P4 CRT

Nov 22, 2006 10:44 PM in response to dotnet

Oh dear, that one again. The disks are running
well within manufacturer specs.

Nope! You're totally wrong and you are misleading others
by sayig so within an OTHERWISE intelligent discussion.

If you like your HardDrive you better NOT EVER EVER
EVER let it reach the manufacturer Max value. Running it
even near the max will reduce performance and DRASTICALLY
decrease it's lifespan. Target temp for almost all HDD
units on the market or in use today is 30c. I can't
stress this strongly enough! Niether can I state strongly
enough how dilluded and just plain dumb anyone would be to
think otherwise.

Including the hard drive vendor?

Heck yeah!

I grant you that vendors can be thoroughly deluded,

And have an adgenda! Like selling you MORE drives. Ever
hear of "pre-engineered failure" sometimes part of "reliability
engeneering"? It's built into just about every automobile
and applience that you use. Why would HDDs be any different?
And why can't overstating thermal limits there-by diminishing
the life-span of a device be part of that?

however, your
frantic handwaving is so much less convincing to me
than this (from Maxtor's KB):

I'm not here to "convince" you of anything. Just letting
folks know what I know and discussing it. It's fun.

I'll choose to believe Maxtor

There's a sucker born every minute. 😉

until you can provide some factual backup for
your assertion.

I did that in the last thread and you chose to ignore it.
http://www.digit-life.com/articles2/storage/hddpower.html

dotnet

Level 1

120 points

Nov 22, 2006 10:50 PM in response to Tesselator

until you can provide some factual backup for
your assertion.

I did that in the last thread and you chose to ignore it.
http://www.digit-life.com/articles2/storage/hddpower.html

I didn't ignore it, I read it. However, this article provides no backup for your theory whatsoever. It just states it as if it were a fact, without any reference, like you do. The rest of the article then goes on about how to properly measure heat dissipation. That's what it is mostly about.

Cheers
Steffen.

Nov 22, 2006 11:41 PM in response to dotnet

Here's another one. From Seagate this time:

http://www.seagate.com/docs/pdf/whitepaper/TP552SV35HeatMay06.pdf
"Excessive heat can undermine this sensitive relationship
in a number of ways.The read/write head rides on a cushion
of air pressure above the platter surface; should the drive
case become too hot ( over 35C ), the air inside expands so
much that it affects the flying height of the read/write
head. While drives are designed to compensate for changes
in head/platter spacing, such compensation degrades signal
integrity, alters the media’s magnetic properties and, in
extreme cases, can lead to data loss."

etc. etc. I'm sure you know how to use a search engine.
Don't you?

.

Dec 1, 2006 3:55 AM in response to dotnet

I didn't ignore it,

Uh-huh...

This thread has been closed by the system or the community team. You may vote for any posts you find helpful, or search the Community for additional answers.

Mac Pro Temperature question