Abit AI7-G with 3.0 GHz Prescott - high temperatures!

x-posted to alt.comp.hardware.overclocking, alt.comp.periphs.mainboard.abit

Hello All

This concerns an as-yet unmodified 3 GHz Prescott CPU - I can't risk
overclocking it until I get the following details addressed:

Can anyone point me to a forum or URL which has discussed the temperatures
of this combination please? My machine is seeing a fairly constant CPU
temperature of 69 deg C (+/- 1 deg C), and 66 deg C for the PWM sensor under
full load. The case temp. is sat at 39 deg C. When I am idling, the temps
drop by about 8 or 9 degrees C.

I want to see if others have seen similar temperatures - this is very high
in my opinion but I question the accuracy of the uGuru monitoring software
(the BIOS seems to correspond however). I appreciate that Prescott cores
run hotter, but surely not this hot!

My Northwood 2.4 GHz was never much above 55 deg C on my Abit BD7-II -
perhaps I should stick it in my AI7-G and compare tempoerature readings as a
method of testing the accuracy of the figures I mention.

This is with the standard supplied Intel cooler - I tried a Coolermaster
heatpipe cooler but that was about 4 degrees C hotter. I have the two fans
on the PSU extracting hot air OUT of the case, one rear fan drawing cold air
into the case, and a final fan extracting the air out of the front of the
case. the CPU and NB fans are free-running inside (not in any ducting).

TIA for any pointers, comments, experiences.

Cheers

RMC, England

> This is with the standard supplied Intel cooler - I tried a Coolermaster
> heatpipe cooler but that was about 4 degrees C hotter. I have the two
fans
> on the PSU extracting hot air OUT of the case, one rear fan drawing cold
air
> into the case, and a final fan extracting the air out of the front of the
> case. the CPU and NB fans are free-running inside (not in any ducting).

Your back fan is pulling WARM air into the case from the PSU... Turn it
around so it's also blowing out. Turn the front one around as well, so it
will pull COOL air from the front of the PC.

I note whilst your CPU temp is 69oC, your case temp is 39oC.
o For the UK that is a rather high case temperature in ~20-22oC room
o Generally you should expect to be around 32-34oC

Firstly - are the temp sensor correct, or is it subject to tolerance
o Temp readings can be out by 10% quite normally
---- thus your CPU could be ~62oC and your case 34oC
o Which would mean you are within Prescott PC ball-park

Secondly - is the cooling set up correctly
o High case & CPU temperature indicates high heat recycling
o CPU & Graphics card coolers merely blow case air at a heatsink
---- your cooling effectiveness (delta-T) depends on case-ambient
o Case temperature is thus a factor in CPU & Graphics CPU temps
---- if the case exhaust fans are not removing air fast enough
---- then the coolers will recycle that hot air, increasing temps

Most CPU coolers recirculate the air inside the case:
o Impingement heatsinks recirculate ~40-70% of their own air
---- impingement is where a fan blows against a heatsink plate
o Blow-through heatsinks recirculate ~20-50% of their own air
---- blow-thro coolers have air blowing straight through the heatsink
---- thus exit air velocity tends to be higher & distant from fan intake

The more a cooler recirculates its own air, the less effective it is.

To resolve this, typically a PC case uses exhaust fans near the CPU
cooler to remove this heated air before it can be recirculated. That is
the idea behind the AMD-approved PSU (PSU intake on the bottom
near the CPU cooler) or a case exhaust fan behind the CPU cooler.

If you have open fan ports in the rear-top of your PC, either block
them off (to stop the short-circuiting of airflow path) or fit a fan there.
The airflow path should be in at the front-bottom, out at top-rear by
both AMD & Intel design guidelines. BTX will differ a little re design.

That your case temperatures are nearly 40oC on UK 20-22oC days
does suggest your exhaust fans are not removing air fast enough. The
P4-Prescott does dissipate ~50W at idle (versus 35W for Northwood)
and ~105 under full load (perhaps artificial load unless games used).
Graphics cards can also dissipate a considerable amount of heat also,
if lower power onboard graphics are used it still needs factoring in.


If your hard-drive supports S.M.A.R.T. reporting, that is another
data-point in validating your other reported temperatures. Programs
such as MBM or HDDTemp can report the HD temperature, which
in a 39oC case temperature may be relatively high - ideal is <50oC.

A hot running HD can be tackled by a small fan in front of them, it
need not be high power - HDs do not dissipate many watts and so
a low cfm fan is quite adequate.


If your case exhaust fans check-out ok (present or holes blocked),
then you may want to verify your intake is sufficiently free flowing.
o 84% of a PCs airflow resistance comes from the fan grills
---- typically these are punched-slots - often flowing just 45-55% air
---- conversely, round-wire grills flow some 89-91% air
o PCs breathe through the lowest common denominator
---- typically this is a slot in the bottom of the front plastic fascia
---- a slot of 3"x1" has a c/s area equivalent to 1/3rd of one 80mm fan

Whilst the reported temperatures are subjecto to normal variation, and
10% is pretty much a given, the case temps indicate things are warm.
I think the HD temperature reported by S.M.A.R.T. will be a useful
data-point here in terms of act / don't act re enclosure cooling. The HD
has to just run 11oC above case ambient to sit on the 50oC level, and
relatively speaking ambient (outside case) temps are muted right now.

Worth checking your heatsink is seated correctly, but if you remove
the factory heatsink you need to replace the TIM (thermal pad) as it
is a once-use item (use thermal compound). Another test is to remove
the case side with the computer running - if case temperatures drop
then your exhaust fans are not removing heated air quickly enough.

CPU coolers work from case-ambient, not room-ambient.
BTX hopes to resolve that somewhat with the CPU taking air in thro
the case fascia and so effectively getting closer to case = room-ambient.
However, CPU & Memory VRM, graphics card, CPU & RAM intend
to share that single fan for their cooling in a "tunnel" - a tall order. The

Prescott runs hot - future chips will be based on cooler P-M architecture,
which tends to case some of the incentive for BTX into some doubt. So
check your HD temp (validity of case/cpu reported temps), then try the
case with the side off briefly (validity of insufficient exhaust fans/cfm).
--
Dorothy Bradbury
www.stores.ebay.co.uk/panaflofan for quiet Panaflo fans & other items
www.dorothybradbury.co.uk (free delivery)

"RMC" <> wrote in message
news:...
> x-posted to alt.comp.hardware.overclocking,
> alt.comp.periphs.mainboard.abit

> Can anyone point me to a forum or URL which has discussed the temperatures
> of this combination please? My machine is seeing a fairly constant CPU
> temperature of 69 deg C

Wow - thanks Noozer and Dorothy! A very comprehensive response indeed. I
will digest the info and modify my airflow direction accordingly.

I'll report back later this weekend and let you know the result ... thanks
once again both of you

RMC, England

"RMC" <> wrote in message
news:...
>
> "RMC" <> wrote in message
> news:...
> > x-posted to alt.comp.hardware.overclocking,
> > alt.comp.periphs.mainboard.abit
>
> > Can anyone point me to a forum or URL which has discussed the
temperatures
> > of this combination please? My machine is seeing a fairly constant CPU
> > temperature of 69 deg C
>
> Wow - thanks Noozer and Dorothy! A very comprehensive response indeed. I
> will digest the info and modify my airflow direction accordingly.
>
> I'll report back later this weekend and let you know the result ... thanks
> once again both of you
>
> RMC, England
>
>
Man, first of all... And this is for everyone here..
(Prescott) runs hot!!
Intel's suggested idle temp is somewhere around 60ºC for the Prescott.
This is one of the main reasons I don't want one.
Reaching temps over 70ºC is not uncommon for the prescott.
I think it's burn out temp is around 90ºC or more, LOL, Might as well fry
an egg on it.
Anyway, if you want lower temps, get a water cooler.

Denny. ;-) :-)

> This concerns an as-yet unmodified 3 GHz Prescott CPU - I can't risk
> overclocking it until I get the following details addressed:
<snip>

Well, thanks to advice from Noozer and Dorothy, I have redirected my airflow
and my case temperature has dropped from about 39 deg C (indicated) to a
constant 27 deg C - this is under load. My CPU and PWM temps have dropped
by a couple of degrees C, to 67 degrees for both of them.

As Denny also suggested, a water cooler would help get my CPU temperature
further lowered but with the associated bulk and cost of an evaporative
cooler, piping, radiator etc. I am not sure whether I want to go to that
trouble. However, it is a good idea and I will look into it, if I can find
any affordable solutions in Britain. Maybe a peltier system could help
(accepting the condesnation issues).

Once again, thanks for all of your help

RMC, England

> Well, thanks to advice from Noozer and Dorothy, I have redirected my
> airflow and my case temperature has dropped from about 39 deg C
> (indicated) to a constant 27 deg C - this is under load. My CPU and PWM
> temps have dropped by a couple of degrees C, to 67 degrees for both of
> them.


I forgot to add that my idle temperatures for the CPU/system/PWM are
53/24/44 deg C respectively.

Best wishes

RMC, England

I originally said

>> my case temperature has dropped from about 39 deg C (indicated) to a
>> constant 27 deg C - this is under >> >> load. My CPU and PWM temps
>> have dropped by a couple of degrees C, to 67 degrees for both of them. My
>> idle temperatures for the CPU/system/PWM are 53/24/44 deg C
>> respectively.

Now I have done some further experimenting and have got further improvement.
The 80mm fan at the rear-top had a punched-hole grill in the back of the
case - I have cut it completely out with some tinsnips to improve airflow.
I have fitted an 80mm fan on the side wall of the case, and a length of tube
which couples this fan straight down onto the CPU cooler immediately below
it. The "side of case" fan draws cold air in and presents it to the CPU
cooler fan which continues drawing it down onto and through the heatsink
vanes..


I am now seeing lower temperatures still, namely CPU/system/PWM of 56/24/54
deg C. The room temperature is a little bit cooler, maybe that is the 3 deg
C difference in system temperature, but the big drop in CPU and PWM
temperatures is very pleasing.

To sum up: (CPU/system/PWM temperatures in degrees C)

original full load temps were 69/39/66
revised full load temps were 67/27/67
final full load temps are 56/24/54

This is with two instances of Seti@home running per logical processor...idle
temperatures are something like 44/24/32 degrees C.

The cooler on the CPU is the Intel supplied heatsink and fan.



Cheers!

RMC, England

"RMC" <> wrote in message
news:...
> I originally said
>
> >> my case temperature has dropped from about 39 deg C (indicated) to a
> >> constant 27 deg C - this is under >> >> load. My CPU and PWM temps
> >> have dropped by a couple of degrees C, to 67 degrees for both of them.
My
> >> idle temperatures for the CPU/system/PWM are 53/24/44 deg C
> >> respectively.
>
> Now I have done some further experimenting and have got further
improvement.
> The 80mm fan at the rear-top had a punched-hole grill in the back of the
> case - I have cut it completely out with some tinsnips to improve airflow.
> I have fitted an 80mm fan on the side wall of the case, and a length of
tube
> which couples this fan straight down onto the CPU cooler immediately below
> it. The "side of case" fan draws cold air in and presents it to the CPU
> cooler fan which continues drawing it down onto and through the heatsink
> vanes..
>
>
> I am now seeing lower temperatures still, namely CPU/system/PWM of
56/24/54
> deg C. The room temperature is a little bit cooler, maybe that is the 3
deg
> C difference in system temperature, but the big drop in CPU and PWM
> temperatures is very pleasing.
>
> To sum up: (CPU/system/PWM temperatures in degrees C)
>
> original full load temps were 69/39/66
> revised full load temps were 67/27/67
> final full load temps are 56/24/54
>
> This is with two instances of Seti@home running per logical
processor...idle
> temperatures are something like 44/24/32 degrees C.

It's still a lot hotter then a (Northwood) mine is sitting at about 20ºC
I'm not sure on system temps, my GA-8IG1000 Pro don't seem to have
any MBM that checks the system temps.
And most programs I've downloaded don't seem to be able to read it either.
It is very nice to see that you have been able to get the temps down that
far though.
And it's also about time Intel comes out with a cpu that can run under
extreme
conditions. Before this, you couldn't run a Intel P4 in desert conditions.

It might not be on-time for them though, AMD is soon to release their new
FX55
of which I belive will be the first to use a 1GHz effective bus rate.
512 MHz for the upper edge of the clock
512 MHz for the other side.

or, 512 (FSB) x the multiplier.
First release chips sold to dealers only will probably come with an
unlocked multiplier.
Most of the times (Intel) does this too.
The FX55 was supposed to come out in the first 1/4 of 2005, but might come
out before christmas
of this year.
What ever, you didn't want to have to read all of that.

Great Job Getting Your Temps Down..
Denny. ;-) :-)

>
> The cooler on the CPU is the Intel supplied heatsink and fan.
>
>
>
> Cheers!
>
> RMC, England
>
>

"Dennis E Strausser Jr" <> wrote in message
newsqadnTC90aDt0qzcRVn-...
> "RMC" <> wrote in message
> news:...
> > I originally said
> >
> > >> my case temperature has dropped from about 39 deg C (indicated) to a
> > >> constant 27 deg C - this is under >> >> load. My CPU and PWM temps
> > >> have dropped by a couple of degrees C, to 67 degrees for both of
them.
> My
> > >> idle temperatures for the CPU/system/PWM are 53/24/44 deg C
> > >> respectively.
> >
> > Now I have done some further experimenting and have got further
> improvement.
> > The 80mm fan at the rear-top had a punched-hole grill in the back of the
> > case - I have cut it completely out with some tinsnips to improve
airflow.
> > I have fitted an 80mm fan on the side wall of the case, and a length of
> tube
> > which couples this fan straight down onto the CPU cooler immediately
below
> > it. The "side of case" fan draws cold air in and presents it to the CPU
> > cooler fan which continues drawing it down onto and through the heatsink
> > vanes..
> >
> >
> > I am now seeing lower temperatures still, namely CPU/system/PWM of
> 56/24/54
> > deg C. The room temperature is a little bit cooler, maybe that is the 3
> deg
> > C difference in system temperature, but the big drop in CPU and PWM
> > temperatures is very pleasing.
> >
> > To sum up: (CPU/system/PWM temperatures in degrees C)
> >
> > original full load temps were 69/39/66
> > revised full load temps were 67/27/67
> > final full load temps are 56/24/54
> >
> > This is with two instances of Seti@home running per logical
> processor...idle
> > temperatures are something like 44/24/32 degrees C.
>
> It's still a lot hotter then a (Northwood) mine is sitting at about 20ºC

<snip>

> Great Job Getting Your Temps Down..
> Denny. ;-) :-)

Wow, if your Northwood is idling at 20ºC, what is your ambient temps? Are
you using some kind of exotic cooling? 68ºF is pretty cold. Mine will idle
at around 29º when left alone for a while.

RMC - you might also want to consider a blow hole with an 80mm fan cut into
the top. I've noticed a drop of 3-4 degress in the processor temperature
since I've done it.

MC