CPU Temperature

[Toshi1873]

Quite subjective while you saying that.
You have to take into account the room temperature.

For what, the boiling point of water? (just kidding)

Prescotts run a bit hotter too, so you might see temps
of 60C (assume 25C ambient temp) and yet the CPU will
still be stable. My personal comfort zone is 50-55C for
AMD CPUs. Anything over 55C and I'll consider adding a
better heatsink.

 

[Overlord]

The only thing normal about those temps is people bringing back their
systems to the manufacturer with toasted CPUs.

Tell them that you'll either leave with a refund for the system or the system
if they can cut the temps in half for idle. I trust they use thermal paste
between the CPU and heatsink and I trust they have Some Kind of fan
on the heatsink. In any case, that's not your problem, it's Theirs!

Intel CPUs will throttle back when the temps reach a certain point in a
desparate attempt to lower the operating temps. The higher the temps,
the more throttling and the slower the system will run.

Your manufacturer, for these temps, is actually claiming that their systems
run slower than any other Intel 3.06. I wouldn't like to even guess just how
slow your system runs when booted to winders and running idle.

It's highly unlikely that you run any sort of higher graphics games on the
system. If you did, I suspect you could count individual frames by eyeball.

I'm certain that my CPU (P4 3.06gHz) is running far too hot and is the cause
of my unstable PC. The manufacturer claims the temp is normal for this type
of system - which is more like a laptop than a desktop, as the motherboard
and cards are built in behind the TFT screen and the hardrive is built into
it's base.

According to Sisoft Sandra, the CPU runs at 108-113'C during normal
conditions an the top of the unit is hot to the touch. Can I rely on this
software's reading?

I've also heard that a P4 powers down when it reaches are certain temp to
prevent burn out - is there any software that can prove that this is
happening?

All help will be appreciated as this system has been in for repair 3 times
in 6 months and I'm thoroughly sick of it, and I want to look into the
possibility of getting a refund if they cannot supply me with a stable
system.

Thanks in advance

~~~~~~
Bait for spammers:
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postmaster@localhost
admin@localhost
abuse@localhost
postmaster@[127.0.0.1]
(e-mail address removed)
~~~~~~
Remove "spamless" to email me.

 

[Clint]

BTW, I did see idle temps up over 75C once, after rebuilding my system.
Turns out I didn't have the HS properly seated on the CPU. Quickly turned
off the computer, reseated the HS, and get idle temps in the 40 range now.
That's on my desktop, with a P4 2.4GHz processor.

Clint

 

[Dorothy Bradbury]

Just to give you one more data point... My laptop (a Dell Inspiron 9100)
uses a desktop P4 CPU (3.0GHz, 800MHz bus). I haven't seen the temp over
65C.

That's about right:
o Laptops are designed to operate at higher temperatures
---- 89oC being a common absolute limit, 80oC the more usual
o That also means laptops have a lower ambient operating temperature
---- higher operating is due to the low air circulation
---- thus typically they require ambient to be below 35oC, desktop 40oC

CPU temperature wise that is ok - well within the thermal design spec.

The original poster, however, is claiming over 110oC:
o The P4 will throttle severely at those temperatures
---- as commented, the machine will operate somewhat slowly
o Additionally, it is well above the thermal design spec of ~80oC
---- thus there is a risk of damage to the mainboard (socket at least)

So...
o Try to verify that temperature - carefully
---- if you can touch the heatsink, it would be *extremely* hot
---- exit air temperature would also be *extemely* hot
---- 69oC is the touchable temperature limit before pain
o If the mainboard has onboard temperature monitoring, use it
---- Sandra may be miss-reading the temperature
o Then verify the heatsink is seated properly
---- it is quite possible to run a P4 without a heatsink (not advised)
---- in doing so it will run very hot, and very very slowly

In SFF or custom-enclosure environments, it isn't impossible for the
heatsink to be canted at one side - thus thermally somewhat ineffective.

The finger-touch is a good one to verify reported temperatures.

There is one other possibility - the temp monitoring is out of spec:
o Most thermistors have a tolerance of +/- 10%
---- so a 50oC actual temperature may be reported as ~45-55oC
o It isn't inconceivably that a tolerance of +/- 20% may apply
---- at least at the tail end of production distributions
---- since this is not a critical component re operation & QA specs
---- which would mean 50oC actual is reported as ~40-60oC
o For temps of >110oC to be reported, something is "wrong"
---- hence the need for investigation as detailed above

The least likely possibility is the reporting is in Farenheit - 113-F,
however discount that. You need to touch the heatsink & verify
it is properly seated - mechanically this is an important check too.

 

[Phil Weldon]

Threshold of pain induced by heat is 45 degrees C; "69oC is the touchable
temperature limit before pain" is way too high.

--
Phil Weldon, pweldonatmindjumpdotcom
For communication,
replace "at" with the 'at sign'
replace "mindjump" with "mindspring."
replace "dot" with "."


news:[email protected]...

 

[Dorothy Bradbury]

Threshold of pain induced by heat is 45 degrees C; "69oC is the

touchable temperature limit before pain" is way too high.

Yes, that is the Psychophysics definition of the threshold of pain,
although figure varies according to usage, material & subject bias
o Clinical Usage (eg, laser treatment):
---- Psychophysics list temperature threshold for pain as 45oC
o Design Material (eg, product liability):
---- Aluminium 45oC, Phenolic fan blade 61oC, Plastic socket 64-77oC
o Subject Bias (eg, conditioning or reward)
---- Temp perception of "pain" can be overriden beyond burning threshold
---- Coffee tasters report preference for hot coffee, despite it being 60oC
---- Yet 60oC is above the burn threshold, never mind above oral pain threshold

Ok, back to the original poster:
o Poster reports "According to Sisoft Sandra, the CPU runs at 108-113'C"

Want a binary test for a) Sandra is wrong, or b) Heatsink installed wrong
o Sandra is wrong -- if the heatsink is even *remotely* touchable
o Heatsink installed wrong - if the heatsink is cold (canted on black socket)

In Human Factors the guide was commonly 69oC as absolute limit of touchable
temperature before pain was such that it caused involuntary motor reflex. Contrast
with merely sensory pain like touching a 50oC laptop HD and noting "it hurts a bit".
Drug or Physical intervention could affect the latter (eg, TENS, Interferential) in a
limited way - such as 1oC at best on method-of-limits derived sensory threshold.

o User reports back - "it is extremely hot"
---- ok, but he *could* touch it -- you say 45oC, I say it could be up to 69oC
---- whatever, Sandra is miss-reporting 113oC
o User reports back - "it !@!?**! burnt me!"
---- ok, you might argue it could just be 46oC, I say it is around 69oC
---- whatever, the Heatsink is unsuitable for that product
o User reports back - "it feels quite cool"
---- ok, you might argue it could just be 45oC
---- whatever, I say the heatsink is canted on the S478 socket or CPU is not 113oC

The *threshold* of sensing pain at 45oC is good for hard-drives though.

You don't need to do any of this if you can eyeball the S478 socket:
o Even the Intel thermal solution will easily "cant" on the S478 side plastic rails
o Viewing the heatsink from the side will show whether it is canted on the receptacle

Personally I suspect a canted heatsink.

 

[David Maynard]

Yes, that is the Psychophysics definition of the threshold of pain,
although figure varies according to usage, material & subject bias
o Clinical Usage (eg, laser treatment):
---- Psychophysics list temperature threshold for pain as 45oC
o Design Material (eg, product liability):
---- Aluminium 45oC, Phenolic fan blade 61oC, Plastic socket 64-77oC
o Subject Bias (eg, conditioning or reward)
---- Temp perception of "pain" can be overriden beyond burning threshold
---- Coffee tasters report preference for hot coffee, despite it being 60oC
---- Yet 60oC is above the burn threshold, never mind above oral pain threshold

Yes. The issue here is the thermal capacity and thermal resistance of the
thing that's 'hot'. I.E. if it's of low thermal capacity, or has a high
intrinsic thermal resistance, then it (or it's surface) isn't 'that' hot
the instant it comes into contact with a cooler object.

Ok, back to the original poster:
o Poster reports "According to Sisoft Sandra, the CPU runs at 108-113'C"

Want a binary test for a) Sandra is wrong, or b) Heatsink installed wrong
o Sandra is wrong -- if the heatsink is even *remotely* touchable
o Heatsink installed wrong - if the heatsink is cold (canted on black socket)

Those are certainly good things to check but your logic tree is a bit
flawed. e.g. If the heatsink is canted so that it's cold then it is
certainly 'remotely' touchable but Sandra could likely be quite right.

In Human Factors the guide was commonly 69oC as absolute limit of touchable
temperature before pain was such that it caused involuntary motor reflex. Contrast
with merely sensory pain like touching a 50oC laptop HD and noting "it hurts a bit".
Drug or Physical intervention could affect the latter (eg, TENS, Interferential) in a
limited way - such as 1oC at best on method-of-limits derived sensory threshold.

o User reports back - "it is extremely hot"
---- ok, but he *could* touch it -- you say 45oC, I say it could be up to 69oC
---- whatever, Sandra is miss-reporting 113oC

Unless the TIM is poor, corrupted, cocked, etc., and Sandra is monitoring
the processor core temp diode.

o User reports back - "it !@!?**! burnt me!"
---- ok, you might argue it could just be 46oC, I say it is around 69oC
---- whatever, the Heatsink is unsuitable for that product

Or case airflow is insufficient.

o User reports back - "it feels quite cool"
---- ok, you might argue it could just be 45oC
---- whatever, I say the heatsink is canted on the S478 socket or CPU is not 113oC

The *threshold* of sensing pain at 45oC is good for hard-drives though.

You don't need to do any of this if you can eyeball the S478 socket:
o Even the Intel thermal solution will easily "cant" on the S478 side plastic rails
o Viewing the heatsink from the side will show whether it is canted on the receptacle

Personally I suspect a canted heatsink.

I would too except for him saying the suppliers claim it's a 'normal' temp
for their equipment.

 

[kony]

I'm certain that my CPU (P4 3.06gHz) is running far too hot and is the cause
of my unstable PC. The manufacturer claims the temp is normal for this type
of system - which is more like a laptop than a desktop, as the motherboard
and cards are built in behind the TFT screen and the hardrive is built into
it's base.

According to Sisoft Sandra, the CPU runs at 108-113'C during normal
conditions an the top of the unit is hot to the touch. Can I rely on this
software's reading?

I've also heard that a P4 powers down when it reaches are certain temp to
prevent burn out - is there any software that can prove that this is
happening?

All help will be appreciated as this system has been in for repair 3 times
in 6 months and I'm thoroughly sick of it, and I want to look into the
possibility of getting a refund if they cannot supply me with a stable
system.

Thanks in advance

You have omitted (pretty much all of the important data).

What, exactly is this system? Hi-res pics (posted elsewhere,
not to the newgroup, then linked) or link to manufacturer's page
might be useful.

When system "has been in for repair 3 times", were symptoms same?
What did they tell you was wrong with it?

Does the system not have a software hardware monitor or bios
reading of temp and voltages? Forget Sandra, it makes a guess
that could be wildly off target.

Have you done the typical PC troubleshooting measures?
Have you checked all cables and connections, taken voltage
readings, examined heatsink-cpu interface, checked that fans were
working, ran memtest86 to check memory, or any/what other checks?

 

[Dorothy Bradbury]

Those are certainly good things to check but your logic tree is a bit

flawed. e.g. If the heatsink is canted so that it's cold then it is
certainly 'remotely' touchable but Sandra could likely be quite right.

That's my point (further on).

I would too except for him saying the suppliers claim it's a 'normal' temp
for their equipment.

With thermal design limit well below 108-113oC, the supplier is making a
somewhat interesting comment - they may be just making a flippant fob off.

o Establish if the heatsink is seated correctly (and TIM material present/ok)
o Then email intel technical support once temperature is confirmed as >>80oC

 

[David Maynard]

That's my point (further on).

Yes, I know what you 'meant' but you still have, to the inexperienced, the
same condition leading to opposing conclusions

With thermal design limit well below 108-113oC, the supplier is making a
somewhat interesting comment - they may be just making a flippant fob off.

Yes, I wondered about that too but, as I said to him, either they're wrong
about the temperature being 'normal' or they're wrong to dismiss the
problem, and I'm not sure which would be the worse offense.

o Establish if the heatsink is seated correctly (and TIM material present/ok)
o Then email intel technical support once temperature is confirmed as >>80oC

Btw, you're presuming a desktop P4 and the temperature monitored being case
temp. Considering his description of the system being 'like' a 'laptop' in
form it made me wonder if perhaps it uses a mobile P4 and it's die temp
he's seeing (or, even if a desktop P4, die temp).

However, the temp would still not be 'normal'.

As kony pointed out, he's not provided enough information to know what he's
really got.

 

[Nel]

As kony pointed out, he's not provided enough information to know what he's
really got.

<Copied from my post on alt.legal.moderated>

Xperian Plus, P4 3.06gHz, 1024 RAM,17" TFT screen from Higrade Computers,
(www.higrade.com) This model has now been discontinued looking the site, as
there is only the earlier 15" model available
http://www.higrade.com/nqcontent.cfm?a_id=3261. A picture of my model can
be seen here: http://www.talkingpix.co.uk/ArticleXperian.html

Repair 1 - From the moment it came out of the box the first time I knew it
was going back as there was piece of grit/dirt between the screen and the
glass front. Then within minutes of first setting it up (registering XP
etc) it started crashing and was guaranteed to crash within moments of
accessing the Media Center function. The motherboard & CPU were supposedly
replaced

Repair 2 - Within 30 minutes of use after it's return, the machine switched
off without warning - no errors, no reboot - just off. This happened
continuously and even while I was in the BIOS looking for a possible answer,
therefore it was not software related.

Repair 3 - after tolerating the continual crashing for a couple of months
(by now I was using my old beige box which I had upgraded to 2.8gHz ,90% of
the time) the TV card failed - no picture, only sound using aerial or
composite inputs. This was replaced. It was during this repair that I
asked them to look at the temperature of the system and was told in the
engineer's report that this was normal. The TV card was replaced.

Current situation<*> like I stated is that the PC struggles to boot in a
variety of ways - no picture at all, BIOS error, hard drive error, freezing
while Windows loads and if I'm lucky enough to get into Windows, crashing
with minutes. Sometimes the USB mouse will not function, sometimes the
network card is not recognised - I find myself laughing in a perverse way
when a new fault crops up!!

Computers are different in that the owner invariably alters
them from "as supplied", by installing additional software
and hardware and by exposing them to the dangers of viruses,
trojans and other malware from the internet or floppy disk.
Repeated crashing is one symptom of an infected machine and
the hardware could be functioning perfectly.

All of these faults have either occurred without a single additional
software installation or re-occurred when the system has been restored to
factory settings using the backup DVD supplied and also before any internet
access has been attempted (Windows Firewall is enabled in the factory
settings and I have an external router with built-in firewall protection)

On the hardware side, repeated crashing is almost invariably
a temperature problem. Is the computer getting adequate
ventilation? Again, it is hardly the supplier's fault if you
are operating it not in accordance with the manufacturer's
recommendations. For example, not leaving enough free space
behind the processor box is a common error.

As you will see from the pictures in the link above, the Xperian has a very
small footprint and because of this, my system has around 18 inches
clearance behind it. I'm sure this is more than adequate!

I cannot say, from the details that you have supplied, that
this system was unfit for purpose when supplied to you -
even though it clearly appears to be now. Knowing what
faults have been diagnosed and what replacement parts have
been fitted would help. After three or four call-outs, there
should be little of the original machine remaining, if
hardware has been changed, each time!

Like I said above, this model has been discontinued judging by the website's
lack of info on it. Being cynical, the fact that an earlier lower spec
model is still available whereas references to mine have been wiped from the
site, leads me to suspect that there was an inherent problem with the
specification.

AFAIK, you cannot reject something, as being unfit for
purpose, if it has been your own actions that have made it so!

From what you've read, wouldn't you be inclined to want to cut your losses
and reject it?
<End of copied text>

Since posting on here and alt.legal.moderated I have sent a recorded
delivery letter to the company, demanding a full refund and am awaiting
their response (and probable refusal!).

I understand where you are all coming from when you talk about re-seating
heatsinks and whatever, but as this system is under a 3yr warranty, my
meddling inside would surely invalidate this (although I have been sorely
tempted!!)

Thanks for all the replies anyway, and I'll see where my refund request gets
me.

 

[Juhan Leemet]

Yes, that is the Psychophysics definition of the threshold of pain,
although figure varies according to usage, material & subject bias
o Clinical Usage (eg, laser treatment):
---- Psychophysics list temperature threshold for pain as 45oC
o Design Material (eg, product liability):
---- Aluminium 45oC, Phenolic fan blade 61oC, Plastic socket 64-77oC
o Subject Bias (eg, conditioning or reward)
---- Temp perception of "pain" can be overriden beyond burning threshold
---- Coffee tasters report preference for hot coffee, despite it being 60oC
---- Yet 60oC is above the burn threshold, never mind above oral pain
threshold

I recall an (old?) technologist and/or engineer temperature estimation
"trick": if you can hold your finger on a part (such as a heatsink) for 10
seconds before it becomes "unbearable" then the part is approximately 50
degrees C. One has to use some sense, and have a reasonable expectation
that the part is not appreciably above 50 degrees C, before touching it,
else you'll "sear" your fingertip. Did that once: instant callous!
Fortunately, I got my finger off before the flesh cooked underneath.

 

[Dorothy Bradbury]

From the nature of the problem, and risk of user intervention,
I can understand why you do not wish to "go investigating".
o Yes, PCs are meant to be user upgradeable (re slots)
o Yes, it may also give the company some time wasting room

So this is an embedded PC.
o Yes it may be a small form factor motherboard etc
o Dimensionally, that in itself doesn't preclude reliable cooling

Ok...
o Current Status - this machine is defective & under warranty
---- you are entitled to a machine performing to original spec
---- fit for purpose means the machine is reasonably stable

o History - this machine seems to have had many problems
---- but actual cause could vary from assembly, to h/w, to s/w

The issue returns, however, to that CPU temperature issue:
o Shutting down during BIOS screen is quite severe
o That time to shutdown has decreased is also severe
o Both of which *potentially* could be temp induced
---- so your concern over reported temperature is sound

TIM, the thermal interface material, once baked does deteriorate.
Also, semiconductors themselves undergo thermal degradation.

Q: How many exhaust ports are there on this machine?
---- as in how many fans, how strong an airflow & how hot is it?

Q: Have you noticed any thermal related smells?
---- this wouldn't be particularly obvious for a CPU though

Q: Does the machine before it shutdown slow to a crawl in windows?
---- if the machine began to stutter as it heated, the P4 is halting re heat

An overheating P4 will slow down as it exceeds thermal design spec,
which in this case is some 25-30oC *below* the temp being reported.

If you purchased via Credit Card, and the purchase is over £100, then
you benefit from protected under the Consumer Credit Act. So you also
have that option open to you - put everything in writing, keep copies.

There is also the Trading Standards Office, who would be interested.

That the machine is off the website doesn't necessitate a failed design,
you'd need to see inside the latter machine & your machine to compare.
Small form-factors exist with P4s - do a google for Stealth Computer,
Desktop P4s are routinely found in "no space" notebook applications.

 

[kony]

<Copied from my post on alt.legal.moderated>

Xperian Plus, P4 3.06gHz, 1024 RAM,17" TFT screen from Higrade Computers,
(www.higrade.com) This model has now been discontinued looking the site, as
there is only the earlier 15" model available
http://www.higrade.com/nqcontent.cfm?a_id=3261. A picture of my model can
be seen here: http://www.talkingpix.co.uk/ArticleXperian.html

Repair 1 - From the moment it came out of the box the first time I knew it
was going back as there was piece of grit/dirt between the screen and the
glass front. Then within minutes of first setting it up (registering XP
etc) it started crashing and was guaranteed to crash within moments of
accessing the Media Center function. The motherboard & CPU were supposedly
replaced

Repair 2 - Within 30 minutes of use after it's return, the machine switched
off without warning - no errors, no reboot - just off. This happened
continuously and even while I was in the BIOS looking for a possible answer,
therefore it was not software related.

Repair 3 - after tolerating the continual crashing for a couple of months
(by now I was using my old beige box which I had upgraded to 2.8gHz ,90% of
the time) the TV card failed - no picture, only sound using aerial or
composite inputs. This was replaced. It was during this repair that I
asked them to look at the temperature of the system and was told in the
engineer's report that this was normal. The TV card was replaced.

Current situation<*> like I stated is that the PC struggles to boot in a
variety of ways - no picture at all, BIOS error, hard drive error, freezing
while Windows loads and if I'm lucky enough to get into Windows, crashing
with minutes. Sometimes the USB mouse will not function, sometimes the
network card is not recognised - I find myself laughing in a perverse way
when a new fault crops up!!



All of these faults have either occurred without a single additional
software installation or re-occurred when the system has been restored to
factory settings using the backup DVD supplied and also before any internet
access has been attempted (Windows Firewall is enabled in the factory
settings and I have an external router with built-in firewall protection)


As you will see from the pictures in the link above, the Xperian has a very
small footprint and because of this, my system has around 18 inches
clearance behind it. I'm sure this is more than adequate!


Like I said above, this model has been discontinued judging by the website's
lack of info on it. Being cynical, the fact that an earlier lower spec
model is still available whereas references to mine have been wiped from the
site, leads me to suspect that there was an inherent problem with the
specification.


From what you've read, wouldn't you be inclined to want to cut your losses
and reject it?
<End of copied text>

Since posting on here and alt.legal.moderated I have sent a recorded
delivery letter to the company, demanding a full refund and am awaiting
their response (and probable refusal!).

I understand where you are all coming from when you talk about re-seating
heatsinks and whatever, but as this system is under a 3yr warranty, my
meddling inside would surely invalidate this (although I have been sorely
tempted!!)

Thanks for all the replies anyway, and I'll see where my refund request gets
me.

Excessive temp does seem to be the problem, but otherwise the
power supply is another potential.

Regardless of the problem, you should neither be trying to fix
this yourself or running system in this state. Thoroughly
document all of this and continue to pursue refund of $$$$.

Only after you have exhausted these avenues or "give up", should
you then proceed to change the CPU heatsink interface, heatsink
itself, change cooling or use an alternate power supply. Given
the form-factor of the unit these things may be beyond the skill
level of most users, the system might be best used with a
downgraded, much slower/cooler/less power hungry CPU in it... or
if bios allowed underclocking and/or undervolting the CPU that
might help too, but again it's not something to try unless you're
"stuck" with the unit and no chance of refund.

 

[Nel]

Q: How many exhaust ports are there on this machine?
---- as in how many fans, how strong an airflow & how hot is it?

2 - exluding the PSU. The top of the casing, where one of the exhausts was
situated was very hot - considering we're talking about the outer case of
the unit!

Q: Have you noticed any thermal related smells?
---- this wouldn't be particularly obvious for a CPU though No

Q: Does the machine before it shutdown slow to a crawl in windows?
---- if the machine began to stutter as it heated, the P4 is halting re

heat
Never really noticed that TBH. That's why I asked the question at the
begining of the thread, to see if there was software that could show this.

An overheating P4 will slow down as it exceeds thermal design spec,
which in this case is some 25-30oC *below* the temp being reported.

If you purchased via Credit Card, and the purchase is over £100, then
you benefit from protected under the Consumer Credit Act. So you also
have that option open to you - put everything in writing, keep copies.

I did buy using a credit card, and that will be an option I will take up if
it comes to it. My recorded delivery letter to the manufacurer was signed
for on 12 August. How long should I wait for any response?

There is also the Trading Standards Office, who would be interested.

Another option that is awaiting my response

That the machine is off the website doesn't necessitate a failed design,

I would say it was highly suspicious though, when the current shown model is
inferior in every way, screen size, CPU, Operating System etc. (Mine has XP
Media Center). When have you seen PC specs go backwards?!!

 

[Dorothy Bradbury]

Q: How many exhaust ports are there on this machine?

2 - exluding the PSU. The top of the casing, where one of the exhausts was
situated was very hot - considering we're talking about the outer case of
the unit!

Could be a passive heatsink on the CPU.

Two exhaust ports excluding the PSU is reasonable, unless super-low airflow.
o Twin 25cfm fans are about 23dB(A) - so very quiet
o That 50cfm is enough to cool 250W - *before* airflow restrictions

Therein lies the issue - airflow restrictions matter in small form factor, and
airflow management (ducts) matters even more if passive heatsinks are used.

That the top of the case is "very hot", whilst subjective, suggests 45oC to 60oC.

If you can shine a torch in through that fan port, can you see a heatsink?

Another issue is the design of the fan ports - tightly spaced horizontal slots
can reduce free-airflow to as low as 33%, even PC-like-holes just 45-55%.
The intake may similarly be restrictive/undersized for two exhaust fans.

The typical low-height P4 heatsinks are "1U" referring to rack application:
o 1U with fan - active cooler - are about 40mm high, and tend to be *noisy*
o 1U without fan - passive cooler - are about 32mm high, skived copper
---- skived copper meaning very-thin, very tightly packed copper fins

Skived copper heatsinks require *high* *direct* airflow to work properly.
If you've ever seen a standard Intel retail P4 heatsink it is an aluminium extrusion,
with relatively few thick fins somewhat widely spaced - low airflow resistance.
A skived copper heatsink requires either ducting to an exhaust fan to work,
or typically 40x28mm 11,000-15,300rpm fans to work - noisy 40dB(A)+.