overheating help

[Steven Campbell]

I built my daughter a PC last year and have never been able to solve the
overheating problems.
It is an Athlon 1400 on a ASUS a7v8x board, 256Mb, CDrw & DVD the case
dimensions are (DxWxH)mm 476x185x443 (cheap case from)
<http://www.ebuyer.com/customer/products/index.html?action=c2hvd19wcm9kdWN0X
292ZXJ2aWV3&product_uid=44509>
It has a Thermaltake Silent boost with Arctic Silver 3
An exhaust fan. I cut out the mesh on the back of the case and installed a
wire grill as I felt previously the hot air was bouncing off the mesh and
back into the PC.
I have an 80mm fan at the front / bottom but when I have it running it
increases the CPU temp and decreases the Motherboard temp.
Disconnected it decreases CPU and increases MB temps.
MBM shows the temps with the bottom fan connected sometimes as high as CPU
70, MB 32 not under full load.
With the fan disconnected it shows CPU 62, MB 40 again not under load.
This is all with the side of the case partly off.
The PC is in the corner of the room which is really the only place she can
have it. I don't think that is helping as the hot air has no where to go.
The set up was improved after I added the Silent Boost to it just before
Christmas but gradually it is getting worse. It has now got to the point
where it freezes occasionally.
The fans are all blowing the way they should and the Silent Boost is
positioned correctly.

Can anyone give me some ideas? I thought maybe the cheap case wasn't helping
but am reluctant to shelling out a lot of cash to find it doesn't help. If
it was guaranteed then it would be no problem.

cheers

Steven.

 

[Martin]

I built my daughter a PC last year and have never been able to solve
the overheating problems.
It is an Athlon 1400 on a ASUS a7v8x board, 256Mb, CDrw & DVD the case
dimensions are (DxWxH)mm 476x185x443 (cheap case from)
<http://www.ebuyer.com/customer/products/index.html?action=c2hvd19wcm9kdWN0X
292ZXJ2aWV3&product_uid=44509>
It has a Thermaltake Silent boost with Arctic Silver 3
An exhaust fan. I cut out the mesh on the back of the case and
installed a wire grill as I felt previously the hot air was bouncing
off the mesh and back into the PC.
I have an 80mm fan at the front / bottom but when I have it running it
increases the CPU temp and decreases the Motherboard temp.
Disconnected it decreases CPU and increases MB temps.

Steven,

You may want to try fitting this fan the other way round.

Martin

 

[philo]

I built my daughter a PC last year and have never been able to solve the
overheating problems.
It is an Athlon 1400 on a ASUS a7v8x board, 256Mb, CDrw & DVD the case
dimensions are (DxWxH)mm 476x185x443 (cheap case from)
<http://www.ebuyer.com/customer/products/index.html?action=c2hvd19wcm9kdWN0X
292ZXJ2aWV3&product_uid=44509>
It has a Thermaltake Silent boost with Arctic Silver 3
An exhaust fan. I cut out the mesh on the back of the case and installed a
wire grill as I felt previously the hot air was bouncing off the mesh and
back into the PC.
I have an 80mm fan at the front / bottom but when I have it running it
increases the CPU temp and decreases the Motherboard temp.
Disconnected it decreases CPU and increases MB temps.
MBM shows the temps with the bottom fan connected sometimes as high as CPU
70, MB 32 not under full load.
With the fan disconnected it shows CPU 62, MB 40 again not under load.
This is all with the side of the case partly off.
The PC is in the corner of the room which is really the only place she can
have it. I don't think that is helping as the hot air has no where to go.
The set up was improved after I added the Silent Boost to it just before
Christmas but gradually it is getting worse. It has now got to the point
where it freezes occasionally.
The fans are all blowing the way they should and the Silent Boost is
positioned correctly.

Can anyone give me some ideas? I thought maybe the cheap case wasn't helping
but am reluctant to shelling out a lot of cash to find it doesn't help. If
it was guaranteed then it would be no problem.

cheers

Steven.

I've found that getting a *good* cou cooler to be considerably more critical
than the case the machine is built in. I've purchased quite a few cpu
coolers
that just plain did not do the job...even though...according to their
ratings
they should have worked.
I think I'd replace your cpu cooler with a better one.

I took a peek at the website for the cpu cooler you have...
and I have a similar unit (not sure if it;s the same one)
I found it worked well with cpu's of 1 ghz or less...but with a fatser cpu
i was getting "higher" cpu temps

 

[Steven Campbell]

I've found that getting a *good* cou cooler to be considerably more
critical

than the case the machine is built in. I've purchased quite a few cpu
coolers
that just plain did not do the job...even though...according to their
ratings
they should have worked.
I think I'd replace your cpu cooler with a better one.

I took a peek at the website for the cpu cooler you have...
and I have a similar unit (not sure if it;s the same one)
I found it worked well with cpu's of 1 ghz or less...but with a fatser cpu
i was getting "higher" cpu temps

I had the original CPU cooler on it then changed to Coolermaster then
changed to the Thermaltake SilentBoost. The SilentBoost is rated up to XP
3400 and has got excellent write ups everywhere I've looked. I'd gladly
change it again if there was a cooler that would do the job but I honestly
think the one that is on it just now is ok. What is concerning me most is
that the temps have been gradually getting worse. Can the Arctic Silver
deteriorate that quickly (8 months).

I'm going to bring the PC downstairs and clean it all and do as Martin has
suggested and turn the fan round first to see if that helps any.

cheers

Steven.

 

[Andy]

he way they should and the Silent Boost is

positioned correctly.

Can anyone give me some ideas? I thought maybe the cheap case wasn't helping
but am reluctant to shelling out a lot of cash to find it doesn't help. If
it was guaranteed then it would be no problem.

cheers

Steven.

Some points have been covered already. IMHO it is not necessarily the Heat,
I have plenty of PCs running in the region of 70/32c

Is it possible for you to borrow another PSU ? Same question for some RAM.

I would suggest that the freezing could easily be caused by either of these
2 items as well as the Heat.

Hope this helps

Andy

 

[Kevin Lawton]

| I built my daughter a PC last year and have never been able to solve
| the overheating problems.
| It is an Athlon 1400 on a ASUS a7v8x board, 256Mb, CDrw & DVD the case
| dimensions are (DxWxH)mm 476x185x443 (cheap case from)
|
<http://www.ebuyer.com/customer/products/index.html?action=c2hvd19wcm9kdWN0X
| 292ZXJ2aWV3&product_uid=44509>
| It has a Thermaltake Silent boost with Arctic Silver 3
| An exhaust fan. I cut out the mesh on the back of the case and
| installed a wire grill as I felt previously the hot air was bouncing
| off the mesh and back into the PC.
| I have an 80mm fan at the front / bottom but when I have it running it
| increases the CPU temp and decreases the Motherboard temp.
| Disconnected it decreases CPU and increases MB temps.
| MBM shows the temps with the bottom fan connected sometimes as high
| as CPU 70, MB 32 not under full load.
| With the fan disconnected it shows CPU 62, MB 40 again not under load.
| This is all with the side of the case partly off.
| The PC is in the corner of the room which is really the only place
| she can have it. I don't think that is helping as the hot air has no
| where to go. The set up was improved after I added the Silent Boost
| to it just before Christmas but gradually it is getting worse. It has
| now got to the point where it freezes occasionally.
| The fans are all blowing the way they should and the Silent Boost is
| positioned correctly.
|
| Can anyone give me some ideas? I thought maybe the cheap case wasn't
| helping but am reluctant to shelling out a lot of cash to find it
| doesn't help. If it was guaranteed then it would be no problem.

Whoa ! - that CPU temp is a bit high !
The Thunderbird core does give off a bit of heat - but I'd say that's a
bit much. Try to get it down to around 50 - 55 if you can.
First off - I'd dismount the HSF and clean everything off - carefully ! No
traces of sticky goo left, and then just use a little Artic Silver and
re-mount.
The fact that you used an inexpensive case shouldn't cause the problem,
but if reversing the front fan to make it blow out instead of in actually
improves the situation, then it shows that something strange is happening
inside the case with the airflow. A 'rats nest' of ribbon cables can
sometimes disrupt the cooling enough - repositioning them, or replacing with
'round' cables might do the trick.
Does your front case fan have a good path to suck cool air in ?
Some cases rely on air flowing from the surface of the front panel
(plastic) which faces the floor. One of mine is like this. I had to file
the 'slots' out into a big hole (it doesn't show as it faces downwards) and
mount the case on taller feet to get air into the case properly.
If that intake fan on the front of the case can't drag planty of cool air
in then you've got no chance !
Occasonally, re-mounting the fan on the heatsink - so that it sucks
instead of blows - has the desired effect. You still get the same total
amount of air flowing through it, just in the other direction. It only takes
a few minutes to try it.
In extreme cases, it can be necessary to cut a hole in the side panel and
mount another intake fan. Using a filter on the outside will both stop dust
being blown in and keep it looking tidy. Seeing as how it is only a 1.4 GHz,
and you're not overclocking, this shouldn't be necessary.
It might be that a different design of HSF suits your particular
circumstances. I've had some very good results with the CoolerMaster 'Aero'
HSFs. Radial fans are quieter and more efficient (better air pressure) and
also drag the air in from a different position. It is possible to re-mount
the Aero fan on the heatsink in different positions to use air from a
different direction.
All the above are ideas, not definite solutions, I'm afraid. Do let us
know how it goes.
Kevin.

 

[w_tom]

How much Arctic Silver have you applied? If it spreads out
beyond the center half of CPU / heat sink interface, then you
have applied too much. Too much thermal compound causes less
cooling.

Chassis fan only determines interior chassis temperature.
It does not matter where air is bouncing around. Simple heat
equation makes that obvious. The temperature of incoming air
and the CFM of that 80 mm fan determines chassis temperature.
More air flow (more CFM) means cooler chassis. It does not
matter which direction air flows. CFM (amount of air moved
through chassis) and temperature of incoming air is only
important. However reversing fan direction can correct a hot
spot problem really created by improperly placed ribbon
cables. But ribbon cables will not obstruct airflow from a
CPU fan; change CPU temperature. Only importance of chassis
fans is that they all move sufficient CFM of cool air into
chassis. Nothing more.

CPU temperature is mostly a function of 'interface
changes'. The best thermal conduction involves minimum
material changes. Best conductivity is CPU direct to
heatsink. A thermal path from 'CPU to thermal compound to
heatsink' is less conductive. Thermal compound - least amount
possible - only fills microscopic holes. Compound must not
obstruct the larger number of CPU direct to heatsink contacts
- where best thermal conductivity lies. As noted, if thermal
compound spreads out into outer half of heatsink or farther,
then you have worsened thermal conductivity - caused
temperature increases.

Another thermal (material) interface is air to heatsink.
Don't concern yourself with this problem. That was
(supposedly) solved by your heatsink fan manufacturer. How
well he solve the problem is defined in a parameter discussed
two paragraphs below.

Critical to a CPU heatsink interface is pressure holding two
materials together. Heatsinks (properly manufactured) are not
perfectly flat. They are constructed so that maximum pressure
appears where almost all heat transfers - in the center - the
only spot that should have thermal compound. Having said
this, some heatsinks are not even machined. Instead, they
would place an inferior thermal pad or thermal tape so that
proper (and more expensive) surfacing is not required.

Better manufacturers will provide a parameter that
summarizes quality of this thermal interface: degree C per
watt. Most of those long winded reviews can be stripped down
to a table: degree C per watt. Any heatsink that does not
provide this number is suspect.

70 degrees is not really a problem since CPU can increase to
90 degrees without adverse effects. However 70 degrees
suggests your heatsink to CPU interface does have a minor
problem; or what is reporting temperature is not accurate.
Too much thermal compound or insufficient contact (pressure)
between heatsink and CPU could contribute. The one 80 mm fan
(that is more than sufficient to move necessary CFM out of
chassis) is not a problem as long as chassis temperature is
being reduced (incoming air is cool). Chassis temperature is
about moving air - cubic feet per minute (CFM) - nothing
more. Does not matter whether that airflow is from sucking or
blowing. Just that cool air enters. Cooling the CPU is about
an interface between materials and a very important parameter
called "degree C per watt".

As for Arctic Silver: expensive hype that is equivalent to
most every other thermal compound. Don't fall for their hype
as made obvious by missing specification numbers on every
Arctic Silver container. They count on you reading those
wordy articles rather than using a simple specification number
- so that you will spend ten times more money for equivalent
product.

 

[Mike Tomlinson]

I had the original CPU cooler on it then changed to Coolermaster then
changed to the Thermaltake SilentBoost. The SilentBoost is rated up to XP
3400 and has got excellent write ups everywhere I've looked. I'd gladly
change it again if there was a cooler that would do the job but I honestly
think the one that is on it just now is ok. What is concerning me most is
that the temps have been gradually getting worse.

Check you've got it on the CPU the right way around. Heatsinks for AMD
chips have a "step" in them which has to be aligned with the raised
portion of the socket. If this is not done, only partial contact
between the heatsink and the CPU die results.

Your Tbird 1400 is noted for being one of the hotter AMD chips; still,
any decent heatsink for recent AMDs should be capable of keeping it cool
enough.

Can the Arctic Silver
deteriorate that quickly (8 months).

Not in my experience; it stays fairly fluid over time, unlike the
cheaper white thermal greases which tend to dry out. I think this is
one of the reasons why you pay the premium for AS.

 

[philo]

I had the original CPU cooler on it then changed to Coolermaster then
changed to the Thermaltake SilentBoost. The SilentBoost is rated up to XP
3400 and has got excellent write ups everywhere I've looked. I'd gladly
change it again if there was a cooler that would do the job but I honestly
think the one that is on it just now is ok. What is concerning me most is
that the temps have been gradually getting worse. Can the Arctic Silver
deteriorate that quickly (8 months).

I'm going to bring the PC downstairs and clean it all and do as Martin has
suggested and turn the fan round first to see if that helps any.

If your's is rated for a 3400 cpu then it was much better than the one i had
and it should definately do the job...

I guess it's possible you used too much thermal grease...
or possibly the fan is not spinning at full speed...

but if you put it on backwards, i'm sure the cpu would have burned up
at once!

 

[Dorothy Bradbury]

o If there is a fan port near the CPU cooler
---- put a fan in it, pulling hot air out (exhaust)
o Verify the air intake holes are free/clear
---- eg, not obstructed by carpet or overly small

An Athlon 1400 does not create a particularly large amount of heat,
it is probably no more than 70W even under absolute maximum load.
In terms of cfm that requires barely more than 14cfm to cool it.

Your cooler is not particularly inefficient - it is reasonably large,
so the issue is then is it 1) fitted correctly 2) excessive thermal
compound 3) recirculating its own hot air. A guide for that is
case temperatures - rear-upper exhaust, front-lower intake.

You can fit all the fans you want, but the weakest link is the size
of the hole that air is drawn into at the front - often very small.

The ideal cases are those where an exhaust fan is fitted behind the
CPU or near the CPU to remove the hot air. Most CPU-coolers
use impingement (fan blowing on a heatsink plate, air forced thro
90-degrees) and as such they can recirculate 40-70% of their air.
So whilst a cooler may only need 14cfm for the heat output of the
CPU, if it recirculates 50% - so 28cfm is needed to compensate.

Case temperatures are one guide, but so are CPU temperatures.

A PC doesn't emit (that) much heat:
o CPU + Graphics + HD/RAM = 75+50+25 = 150W
o PSU will draw 20% more re inefficiency = 180W total

1500W can be cooled by 300cfm, 180W requires 36cfm.
That is not a particularly large - or noisy - amount of airflow.

However, CPU cooler efficiency re not recirculating its own air
is important - air velocity out of a cooler is low, easy to recirculate.

 

[DaveW]

A well designed case with multiple case fans should solve your problem.
Check out Antec cases. They're well ventilated.

 

[w_tom]

Too many people hammer a brad in with a sledge hammer. This
'more fans' post is silly. One standard flow 80 mm fan
provides more than enough cooling for a chassis. This made
painfully obvious by simple multiplication and basic numbers.

Those fans are only for chassis cooling. Adding two more
fans - therefore reducing chassis temperature by a few more
degrees F - is not going to cool CPU by tens of degrees C.
Please learn numbers and basic science before promoting an
advertiser's scam of "more fans" or "more ventilation". If
that recommended chassis was superior, then the claim would
include numbers. Where are the numbers? No numbers means
vendor is selling hype to junk scientists. Again, increased
chassis cooling - even two fans - will do virtually nothing
for a problematic CPU / heatsink interface problem.

Please learn a simple thermal concept before promoting an
advertiser's scam. A previous post introduced those
concepts. I am simply asking you to post with
responsibility. Nothing more. One 80 mm fan is more than
enough for most every CPU system. Will five fans then do
better? Obviously not. Five fans only creates a new problem
- dust blockage. Dust that will only make a CPU cooling
problem worse.

 

[Kevin Lawton]

<snip>
The temperature of incoming air
| and the CFM of that 80 mm fan determines chassis temperature.
| More air flow (more CFM) means cooler chassis. It does not
| matter which direction air flows. CFM (amount of air moved
| through chassis) and temperature of incoming air is only
| important. However reversing fan direction can correct a hot
| spot problem really created by improperly placed ribbon
| cables. But ribbon cables will not obstruct airflow from a
| CPU fan; change CPU temperature.

I once had to fix an overheating PC which had been built with a long
ribbon cable looped inside the case so that it almost sat on top of the CPU
fan. As a result, the fan was not able to shift the full volume of air and
was making a roaring noise, as they do when air flow is obstucted.
Kevin.

 

[Kevin Lawton]

| A well designed case with multiple case fans should solve your
| problem. Check out Antec cases. They're well ventilated.

And expensive !
To be honest, a cheap case fitted with a front intake fan and a rear
exhaust fan should be able to give more than adequate cooling for the system
described. Just be carefull over the details and make sure nothing obstructs
the airflow in and out of the case.
Kevin.

 

[Kevin Lawton]

| Too many people hammer a brad in with a sledge hammer. This
| 'more fans' post is silly. One standard flow 80 mm fan
| provides more than enough cooling for a chassis. This made
| painfully obvious by simple multiplication and basic numbers.

Where should this fan be placed, and which way sould it blow ? At the
front - sucking cool(ish) air into the case to hopefully escape through
various case vents, or at the back - blowing warm air out of the case to be
hopefully replaced by cool air finding its way in through the case vents ?

| Those fans are only for chassis cooling.

Except that every part of a PC turns the electricity it uses into heat.
This will, over a period of time, cause the temperature to rise untill
eventually the unit self destructs. Some disk drives need a little air flow
to keep them at a reasonably sensible temperature.

Adding two more
| fans - therefore reducing chassis temperature by a few more
| degrees F - is not going to cool CPU by tens of degrees C.

Of course not, but a well-placed fan could make the difference between
having the HSF sat in a pool of recycled warm air and fresh cooler air. A
given HSF will have a certain thermal resistance in degrees per watt. It
will therefore, maintain a certain temperature gradient between the CPU
being cooled and the temperature of the air it is sat in. If this internal
temperature is ten degrees higher than the temp outside the case, then the
CPU will end up around ten degrees hotter.

| Please learn numbers and basic science before promoting an
| advertiser's scam of "more fans" or "more ventilation". If
| that recommended chassis was superior, then the claim would
| include numbers. Where are the numbers? No numbers means
| vendor is selling hype to junk scientists. Again, increased
| chassis cooling - even two fans - will do virtually nothing
| for a problematic CPU / heatsink interface problem.

Obviously sellers want to sell as much of their product as possible.
It is common sense that hot air needs to be removed from inside the case
and cool air pushed into it. Five fans is probably overkill for most
systems. One well placed intake fan, and one well-placed exhaust fan is
sensible.

| Please learn a simple thermal concept before promoting an
| advertiser's scam. A previous post introduced those
| concepts. I am simply asking you to post with
| responsibility. Nothing more. One 80 mm fan is more than
| enough for most every CPU system. Will five fans then do
| better? Obviously not. Five fans only creates a new problem
| - dust blockage. Dust that will only make a CPU cooling
| problem worse.

 

[Guest]

It is an Athlon 1400 on a ASUS a7v8x board,

It has a Thermaltake Silent boost with Arctic Silver 3
An exhaust fan. I cut out the mesh on the back of the case
and installed a wire grill as I felt previously the hot air
was bouncing off the mesh and back into the PC.
I have an 80mm fan at the front / bottom but when I have
it running it increases the CPU temp and decreases the
Motherboard temp.
MBM shows the temps with the bottom fan connected sometimes
as high as CPU 70, MB 32 not under full load.
With the fan disconnected it shows CPU 62, MB 40 again not
under load. This is all with the side of the case partly off.

Don't run the computer normally with the side of the case partly
removed. Install it properly, and measure the temperatures again. If
the case is cooler with the fan running, then the fan isn't at fault,
but if the temperature is higher, try reversing the direction of the
fan because fairly airtight cases are usually cooled better when the
case fan brings in air, but fairly leaky cases often benefit more when
the case fan pulls out air.

Why would the CPU run hotter in a cooler case?

Cutting out grills for better cooling is a waste of time, and using
Arctic Silver instead of Radio Shack paste is a waste of money.

How is the clearance around the CPU heatsink and fan? Are any plug-in
cards or cables blocking them? If the power supply mounts vertically,
is there at least 1/2" of clearance between it and the CPU fan? This
is especialy important when the power supply has a second fan on
bottom that sucks air away from the CPU, and in such a situation it
could help to reverse the CPU fan so it blows away from the heatsink.

 

[TMack]

I built my daughter a PC last year and have never been able to solve the
overheating problems.

SNIP!

Have you checked that the fan in your PSU is working properly? These can
fail completely or run slow due to sticky bearings. The PSU sits near the
cpu and can generate a lot of heat - if it isn't being cooled properly then
your cpu fan may be blowing warm/hot air over the cpu.

You will also need to pay more atttention to air flow inside the case if
your cpu fan is simply recirculating the warm air around the cpu instead of
moving it away then it won't be effective - the fact that one case fan makes
such a big difference suggests a major problem with airflow/circulation.

What core voltage are you running the cpu at? Most athlon 1.4s will run at
1.6v core or thereabouts - some are stable at 1.5v so you could try a lower
core voltage.

If all else fails, cut a hole in the side of the case and mount an 80mm case
fan (or larger) blowing down onto the psu - this reduced temps by 5c or more
on my old system.

Tony

 

[Mike Tomlinson]

Obviously sellers want to sell as much of their product as possible.
It is common sense that hot air needs to be removed from inside the case
and cool air pushed into it. Five fans is probably overkill for most
systems. One well placed intake fan, and one well-placed exhaust fan is
sensible.

Agreed, and because hot air rises, it makes sense to have the intake fan
at the front bottom of the case, and the exhaust fan(s) at the rear top.

We've reached a point where CPUs run so hot that an additional case fan
of some form is practically compulsory; IMO the PSU fan should be
regarded as being there to cool the PSU itself (as it contains large
heatsinks) and not the whole system as it used to.

 

[Kevin Lawton]

| <snip>
| Cutting out grills for better cooling is a waste of time,

Oh no it isn't !
Quite often case grills are just a few concentric circles of small holes.
Their total area might amount to less than two square inches. An three-inch
fan has an area of around six square inches, and axial fans an't deliver
much pressure. The net result is that the little holes will both reduce
airflow by increasing air resistance and crate turbulence. This will cause
noise, both from the turbulence and from the roaring noise the fan makes due
to the air resistance. This can be properly measured, and found to be a
surprisingly large effect. If in any doubt, consider the following two:
1) Try running a case fan in free air without a grille. Notice how quite
it is.
2) Try blowing with your mouth into free air, and then at or through an
empty PC case fan grille. Notice how much noise the air makes as it impinges
on grille. Notice also how not all of the air you are blowing passes through
the grille, but bounces off the metal instead.

Kevin.

 

[Robert]

| <snip>
| Cutting out grills for better cooling is a waste of time,

Oh no it isn't !
Quite often case grills are just a few concentric circles of small holes.
Their total area might amount to less than two square inches. An three-inch
fan has an area of around six square inches, and axial fans an't deliver
much pressure. The net result is that the little holes will both reduce
airflow by increasing air resistance and crate turbulence. This will cause
noise, both from the turbulence and from the roaring noise the fan makes due
to the air resistance. This can be properly measured, and found to be a
surprisingly large effect. If in any doubt, consider the following two:
1) Try running a case fan in free air without a grille. Notice how quite
it is.
2) Try blowing with your mouth into free air, and then at or through an
empty PC case fan grille. Notice how much noise the air makes as it impinges
on grille. Notice also how not all of the air you are blowing passes through
the grille, but bounces off the metal instead.

Agreed - this also applies to inlet grilles and frequently poor case
design which impinges on air intake. Provided that the air inlet is
sufficiently large and is not obstructed (apart from a good filter),
intake fans can be dispensed with thus cutting noise down or causing
dust problems.