P3 max temp?

[Stacey]

I'm trying to build an ultra quiet PC for a multimedia image display. Of
course the cooling fans are a problem. Just wondering what kinda temps are
acceptable as a ceiling on a P3 800/133 flip chip as I experiment with
different fans/speeds/coolers etc.? Do they have throttling like the P4's
to keep from roasting themselves? TIA

 

[Grumble]

I'm trying to build an ultra quiet PC for a multimedia image
display. Of course the cooling fans are a problem. Just wondering
what kinda temps are acceptable as a ceiling on a P3 800/133 flip
chip as I experiment with different fans/speeds/coolers etc.?

Pentium III in the FC-PGA2 Package Thermal Design Guidelines
http://intel.com/design/pentiumiii/designgd/24966001.pdf

 

[Tony Hill]

I'm trying to build an ultra quiet PC for a multimedia image display. Of
course the cooling fans are a problem. Just wondering what kinda temps are
acceptable as a ceiling on a P3 800/133 flip chip as I experiment with
different fans/speeds/coolers etc.?

Intel lists the maximum core temperature for the FC-PGA PIII running
at 800MHz as 80C. Of course, you don't want to run the chip at 80C,
probably best to keep it bellow 70C at an absolute max, and ideally
down around 60C max. Given that these temp monitors usually aren't
super-accurate, it's always best to least a bit of room.

Do they have throttling like the P4's
to keep from roasting themselves? TIA

No. Like AMD's AthlonXP chips though, they do have a thermal shutdown
circuit which should be sufficient to kill power to the system before
they fry though. These chips *shouldn't* get fried under any normal
circumstance (ie any situation other than opening up your case and
ripping the heatsink off while the system is running). That being
said, all chips (including the P4s) can be damaged by running them for
prolonged periods in a system without sufficient cooling.

Fortunately the chip you've got doesn't consume very much power and
should be fairly easy to cool. It's TDP is rated at 20.8W, less than
even Intel's Pentium-M and MUCH less than current Athlon or P4
systems. A nice big heatsink with either a slow-spinning 80mm fan
sitting on top or even a passive heatsink with a case fan blowing over
it should do the trick. If you can afford the loss in performance you
can even underclock these chips down to 600/100MHz and undervolt them
by a bit. At default voltage they would have a TDP of about 15W at
600MHz, and if you undervolt them even a bit you should be able to
drop that down to about 10V.

 

[Stacey]

Fortunately the chip you've got doesn't consume very much power and
should be fairly easy to cool. It's TDP is rated at 20.8W, less than
even Intel's Pentium-M and MUCH less than current Athlon or P4
systems. A nice big heatsink with either a slow-spinning 80mm fan
sitting on top or even a passive heatsink with a case fan blowing over
it should do the trick.

I'm going to try one of those zalman Cu "flower" heatsinks made for a socket
A athlon and use as slow a fan as I can get away with. Just wanted to know
what sorta temps would be safe. Right now it never gets over 40C so if 60C
is safe, I got some room. Thanx for everyone's help.

 

[Rob Stow]

Tony Hill wrote:




I'm going to try one of those zalman Cu "flower" heatsinks made for a socket
A athlon and use as slow a fan as I can get away with. Just wanted to know
what sorta temps would be safe. Right now it never gets over 40C so if 60C
is safe, I got some room. Thanx for everyone's help.

I've used one of those with an XP1900+ with no cpu fan -
just a quiet intake fan at the lower front of the case and one
for outtake at the upper rear. CPU temp was about 68'C
under load - a little higher than most people will put up
with, but still well within the safety margins.

When I upgraded to an XP2400+ then cpu temp jumped up to
75'C, but adding a side-panel case fan brought it back down to
70'C. I also found that lying the case on the side drops
the temp down to 67'C - at the expense of making the optical
drives impossible to use.

 

[Robert Myers]

I've used one of those with an XP1900+ with no cpu fan -
just a quiet intake fan at the lower front of the case and one
for outtake at the upper rear. CPU temp was about 68'C
under load - a little higher than most people will put up
with, but still well within the safety margins.

My (ahem) Dell 8100 has no CPU fan as such. The rear case fan
connects to a shroud which surrounds the CPU heat sink and allows air
in only through a gap between the shroud and the motherboard. That
means not only no CPU fan, but the airflow around the heatsink is not
in hair-dryer mode. It works, and it is _very_ quiet.

Jet noise varies inversely as *eighth* power of the area of the jet
for a given volumetric flow, so a big case fan is much quieter than a
little CPU fan to achieve the same airflow. If I really wanted to
build a quiet CPU and didn't want to go completely fanless, that's how
I'd do it.

RM

 

[Rob Stow]

My (ahem) Dell 8100 has no CPU fan as such. The rear case fan
connects to a shroud which surrounds the CPU heat sink and allows air
in only through a gap between the shroud and the motherboard. That
means not only no CPU fan, but the airflow around the heatsink is not
in hair-dryer mode. It works, and it is _very_ quiet.

I've done something like that - sort of - with an XP2400+,
back in the days when the XP2400+ was thought of as a fast
cpu.

The heat sink had vertical fins. Of course.
I had someone with better welding skills than me put a little
piece of aluminum on the top of the sink, plus two more square
pieces with 3" holes on the two open sides of the sink.
So at this stage the outside of the heat sink is closed off
except for the two round holes on opposite sides of the heatsink.

Next I attached a piece of hose (cut from a large diameter
Shop-Vac type hose) to each side of the heat sink. One of
the other ends of the hose I clipped+taped to the case air
intake fan and the other end to one of the case outtake
fans. Presto - el cheapo ducted cooling for the cpu. I soon
found I could get along without the case intake fan and just let
one of the rear outtake fans do all the work of moving air
through the hoses.

It was *very* quiet. So quiet that someone made me an offer
I couldn't refuse for the system - so I sold it to him. Two
weeks later he was back complaining about how noisy it was -
and I opened up the case and saw that my hard work had been
thrown away and replaced with a conventional heatsink+fan.

 

[Felger Carbon]

My (ahem) Dell 8100 has no CPU fan as such.

Your _Dell_? That dastardly supplier what don't do R&D? That makes
highly
unreliable computers?

Wait'll Yousuf hears about this!

Is that really you, Robert, or has an imposter snuck into the NG? ;-)