Fan Noise 540J Processor

[Ken]

I have an Asus P5P800 MB, a 540J processor, 1 Gig of Kingston DDR 400 memory
an ATI Radon 9600 XT video card all in a big mid tower PC 30 Lian Li
Aluminum case. The power supply is a 470 Watt PC Power & Cooling Silencer.
The case has 4 cooling fans, not counting the one in the power supply! I
know the Prescott processors run hotter but the intel supplied heat sink fan
runs @ 5000+ rpm when the system is under load. In fact the heat sink fan
runs at an relatively high rate even when the system is sitting idle for
several hours. The cpu temperature runs between 28C and 50C depending on
the load. What I don't understand is as soon as I take the cover off the
case the heat sink fan gradually slow down to "normal" or 2657 rpm and all
is well no matter how much of a load is on the cpu. During all this the MB
temperature never varies much from 30C. Short of cutting a whole in the
side of my case, does anybody have an idea why the heat sink fan thinks it
has to try to take off when the side cover is on the case?

 

[Mercury]

Cutting a hole in the side of the case may be the best thing to do. There
are bound to be duct kits for this. Line up the hole and duct so that fresh
air is delivered straight to the CPU cooler. You will find this is quite
standard for Intel approved cases.

Before you rip in,check that the fans blow in the right directions - from
what you say, it sounds like they do.

 

[Paul]

Cutting a hole in the side of the case may be the best thing to do. There
are bound to be duct kits for this. Line up the hole and duct so that fresh
air is delivered straight to the CPU cooler. You will find this is quite
standard for Intel approved cases.

Before you rip in,check that the fans blow in the right directions - from
what you say, it sounds like they do.

The explanation is right here:

http://www.tweaktown.com/document.php?dType=review&dId=220&dPage=3

"Due to the case being so small, the power supply unit needs to
be mounted vertically rather than the usual horizontal mounting.
This means that the PSU sits directly on top of the CPU and on some
motherboards, the memory slots as well."

As some people have noted in the past, buying a taller case, leaving
more room between the PSU and the CPU heatsink/fan, can improve the
air flow. Based on that description above, I don't know if you can
find a way to mount ducting or not.

I've noticed, when examining the results of using a Zalman 7000
heatsink/fan, that there is a warm "cloud" of air around the
heatsink/fan. That can mean the fan is breathing its own exhaust,
over and over again (think recirculation ratio). With a properly
designed duct, the recirculation ratio can be dropped quite a bit,
so the fan only gets fresh outside air.

The Intel fan senses air temperature, and doesn't sense the heatsink
temperature. That is why it should take some time before it speeds
up, until the case air is again heated above the threshold for the
Intel fan.

There are other cooling concepts, like the BTX wind tunnel
cooling design. Or things like this, which may be too tall to
fit under your PSU:

http://usa.asus.com/prog/spec.asp?m=Star Ice&langs=09

The trouble with side mount (wind tunnel) coolers, is cooling
performance. At 0.39C/W, if your room was 25C, processor was
dissipating 100 watts, the CPU case temp would be 25+100*0.39=64C.
This would clearly be a marginal design, in an un-airconditioned
room in the summer. A cooler rated at 0.20-0.25 would allow more
design margin.

http://www.tomshardware.com/firstlook/20050104/asus-starice-05.html

An XP-120 (or a zalman 7700) and a tower case will give optimal
cooling. Perhaps you have a lower powered computer you could stick
in the PC30 case ?

HTH,
Paul

 

[Ken]

How big a case is "big". The one I got is 100% aluminum 8.25" Wide by
19.25" Deep by 17.5" High. There is lots of room in side the case and the
Power Supply is 2" above the cpu heat sink. Maybe I need to reverse a few
of the fans and blow air into the case instead of out?

 

[Michael W. Ryder]

I have an Asus P5P800 MB, a 540J processor, 1 Gig of Kingston DDR 400 memory
an ATI Radon 9600 XT video card all in a big mid tower PC 30 Lian Li
Aluminum case. The power supply is a 470 Watt PC Power & Cooling Silencer.
The case has 4 cooling fans, not counting the one in the power supply! I
know the Prescott processors run hotter but the intel supplied heat sink fan
runs @ 5000+ rpm when the system is under load. In fact the heat sink fan
runs at an relatively high rate even when the system is sitting idle for
several hours. The cpu temperature runs between 28C and 50C depending on
the load. What I don't understand is as soon as I take the cover off the
case the heat sink fan gradually slow down to "normal" or 2657 rpm and all
is well no matter how much of a load is on the cpu. During all this the MB
temperature never varies much from 30C. Short of cutting a whole in the
side of my case, does anybody have an idea why the heat sink fan thinks it
has to try to take off when the side cover is on the case?

I am using a similar setup with a 9700 Pro instead of the 9600 Pro and
had to use a much taller case to get the cooling to work. The mid tower
I was using before did not leave any room around the fan for it to work.
Going to a full tower aluminum case dropped my idle temperatures more
than 10 degrees Centigrade.
Your current case is much too small for your setup. Adding a side fan
may work but I didn't try this as it wasn't worth the effort for me.

 

[Ken]

I'm sorry---the case I am using is the Lian Li PC 61 not a PC 30!! Based on
all the input I guess I should look a getting a PC 71? Seems like over kill
to me.

 

[Roger Hamlett]

I'm sorry---the case I am using is the Lian Li PC 61 not a PC 30!!
Based on all the input I guess I should look a getting a PC 71? Seems
like over kill to me.

How many of the fans are intakes, and how many are outgoing?. One reason a
fan will spin fast, is if the pressure in the case is dropping. If (for
instance), the front fan is reversed, and extracting air, and all the rear
fans are outgoing, then your case is reliant on air seeping in round the
panel edges, or through the CD drive. This howver normally only causes a
few hundred RPM change. The fact that the temperature is higher with the
case on, implies that either this is happening, or the fan is speeding up
because the area where it's sensor is placed, is no longer receiving cold
air when the case is on (again intake problems).
Look at where the cold air gets into your case.

Best Wishes

 

[RBM]

I would check to be sure your two front fans are blowing in and the rear and
blowhole fans are blowing out. I would also try removing and reseating the
CPU heat sink. I had mine on I thought correctly and was getting high temps
so I removed and reseated it and found that one leg hadn't caught properly.
Now the Prescott is only hot enough to fry eggs

 

[DaveW]

As you pointed out, the Prescott CPU, runs so hot under load it gets up to
50 C. THAT's why the CPU fan is trying to take off. It's a design problem
with Intel's Prescott's.

 

[Michael W. Ryder]

I'm sorry---the case I am using is the Lian Li PC 61 not a PC 30!! Based on
all the input I guess I should look a getting a PC 71? Seems like over kill
to me.

This case should be OK as far as size goes. You confused me with an
earlier post giving the size of what I thought was a PC-30 being almost
the same size as my current case. The only real difference is my
current case has a side fan blowing in towards the CPU, a second fan in
the rear, and an exhaust fan in the top of the case. You might want to
see about modding your case with the side and top fan and seeing if they
help. I am using the Thermaltake Jungle heat sink and fan and the fan
normally runs about 3,900 RPM with no difference regardless of the load.

 

[Paul]

I'm sorry---the case I am using is the Lian Li PC 61 not a PC 30!! Based on
all the input I guess I should look a getting a PC 71? Seems like over kill
to me.

First problem with the case is the grill over the rear fan.
I would snip that out of there with a nibbling tool. If you
are worried about fingers getting to the fan, install a wire
grill where the hole is. That will allow the fan to be more
effective.

Adding a second fan back there, would give a better balance
between the front and rear fans on the case. (The power supply
fan doesn't count, as it runs too slow.) Trouble is, you don't
have room for another 80mm back there, and a 60mm would be
pretty ineffective.

http://www.atruereview.com/PC61/5big.jpg
http://www.atruereview.com/PC61/10big.jpg

As for the processor, you could add a duct from the side of the
computer case, down to the top of the CPU fan.

If you don't like the look of the duct, add the second fan to
the back of the computer, and upgrade the CPU heatsink to something
better. If the Intel HSF is 0.35C/W thermal resistance, then
any heatsink/fan with a rating lower than that will be an improvement.
XP-90, XP-120, zalman 7700, zalman 7000 + S775 adapter ring
are possible solutions.

Your first priority is to get more air out the back of the case.
Adding a duct would be about as effective, as a heatsink/fan
upgrade, but with the difference being, that the duct will
unbalance the inlet versus outlet ratio of the fans. The
CPU fan will be pulling air into the case, making three input
fans, versus whatever you have on the back blowing out.

Paul

 

[timmy]

your front fan should be intake. Intel recomends the side fan mount
for your proccessor as well, so unless you have the proper case(spec),
I would expect more of a challenge for cooling. Of course, adding to
the hot air ciculation problem is that north bridge and faster ddr
memory. This is why the new side mount cooling spec.
Regards,