CPU Fan For LGA775

  • Thread starter Thread starter Clayton
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Clayton

Why do most manufactures sell CPU fans with 3 pins for the LGA775 boards
when they all come with 4 pin headers?

I guess the 4th pin on the motherboard header is for fan control

Trying to find a decent quiet copper based heatsink/fan with copper pipes
but all have 3 pins and my motherboard has 4 pin header.
 
Clayton said:
Why do most manufactures sell CPU fans with 3 pins for the LGA775 boards
when they all come with 4 pin headers?

I guess the 4th pin on the motherboard header is for fan control

Trying to find a decent quiet copper based heatsink/fan with copper pipes
but all have 3 pins and my motherboard has 4 pin header.
Click to expand...

What cheap heatsink/fans are you getting? We have gotten HSF's that
are designed, made and sold specifically for LGA775 installations and
all of our's have 4-pin CPU fans attached to the heatsink.
 
Why do most manufactures sell CPU fans with 3 pins for the LGA775 boards
when they all come with 4 pin headers?

I guess the 4th pin on the motherboard header is for fan control

Trying to find a decent quiet copper based heatsink/fan with copper pipes
but all have 3 pins and my motherboard has 4 pin header.
Click to expand...

Why do you ask HERE when your question has nothing to do with the XP
OS?

Ask elsewhere.
 
I want to replace the stock Intel HSF with something quiet, has copper heat
pipes and fan with 4 pin, what is the best? the Intel one supplied with the
CPU is far to noisy and is only aluminium, I hear copper is better for the
heat than aluminium is
 
Clayton said:
I want to replace the stock Intel HSF with something quiet, has copper heat
pipes and fan with 4 pin, what is the best? the Intel one supplied with the
CPU is far to noisy and is only aluminium, I hear copper is better for the
heat than aluminium is
Click to expand...

The fluid in the heat pipes is hundreds of times more effective at moving
heat, than just metal. The heatpipe(s) should be as close as possible to the
top of the chip package, so they can directly carry the heat from there,
into the fins. Heatpipes are a means, to make distant fins as
effective as if they were right on top of the lid. Normally, the
spread of heat in a solid chunk of metal, reduces the effectiveness
of fins that are a distance from the heat source. With heatpipes at
work, an aluminum fin can be almost as good as a copper one, especially
if the fin is not that tall to begin with. (A tall fin would rely on
the conduction properties of the fin moreso than a less-tall fin.)

The only downside of heat pipes, is they can fail. For example, there is a
tiny quantity of fluid inside the heat pipe, and if that leaves the pipe
for any reason, the pipe is then just a piece of metal. Which is why
it is good if the cooler design uses more than one pipe - if one pipe
fails, you still get some cooling effect from the remaining pipes.

This one has a four pin fan on it, at least as depicted in the
installation manual. There may be others with four pin fans.

http://www.zalman.co.kr/eng/product/view.asp?idx=231&code=009

The diameter of the cooler is such, that it can bump into the
power supply, if it is turned a certain way. The compatibility
page demonstrates the kind of gap that should exist, between the
bottom surface of the power supply, and the upper edge of the
motherboard. Since your system is already assembled, it should be
pretty easy to check the clearance between the power supply
bottom surface, and the edge of the motherboard. (In using this
link, my assumption is the 9500AT and the 9700NT have the same
dimensions. Actually, when I look at the 9500 AT installation
manual, it has a four pin connector on the fan as well.)

(9500 AT page - where I got the second link)
http://www.zalman.co.kr/eng/product/view.asp?idx=193&code=009

(9500 compatibility page)
http://www.zalman.co.kr/product/cooler/9500_LED_775_eng.html

Paul
 
I don't know what the big deal with heatpipes is... A heatpipe can't
transfer heat better than solid metal.

Copper is better, but not a whole lot.

If you want quiet, you want to look for two things... A thermally controlled
fan and a large fan.
 
I might be wrong but to my knowledge, any fan indicated as beeing PWM (or
Pulse Width Modulation) compatible (as is the case with the Zalman CNPS9700
NT and other similar models) is probably a 4 pin fan.
 
Oh, I'm not really against 4 pin fan (but I'm against them if your
motherboard only support 3 pin fan). You can install a 3 pin fan on a 4 pin
header and it should work without any problem but the inverse is not really
true: installatin a 4 pin fan on a 3 pin header will cause you trouble.

In your case, the problem was less with the number of pin than the fact that
the stock Intel heatsinks are usually of minimal quality/performance.
However, even if they are of not so good performer, I don't understand why
it was always running at full speed the whole time. Are you sure that the
CPU Fan speed control wasn't deactivated in the BIOS?
 
Noozer said:
I don't know what the big deal with heatpipes is... A heatpipe can't
transfer heat better than solid metal.

Copper is better, but not a whole lot.

If you want quiet, you want to look for two things... A thermally controlled
fan and a large fan.
Click to expand...

http://en.wikipedia.org/wiki/Heatpipe

"The advantage of heat pipes is their great efficiency in
transferring heat. They are actually a vastly better heat
conductor than an equivalent cross-section of solid copper."

It is the power of a phase change and the heat of
vaporization being given up when the vapor turns
back into fluid, at the fin end of the heatpipe.
That is what carries the heat.

http://en.wikipedia.org/wiki/Latent_heat

Another reference here:
http://www.bmpcoe.org/bestpractices/internal/therm/therm_1.html

"This closed-loop, two-phase mechanism allows heat pipes to
transfer heat at one hundred to several thousand times the
capability of an equivalent-size piece of solid copper"

While heat pipes are amazing, they do have limits. For example,
if you apply too many watts at one end, the heat pipe can be
overwhelmed. So they have to be designed for an expected temperature
and power dissipation range. With solid copper you wouldn't have
to worry about what happens if it gets too hot - the solid copper
still works.

But heatpipes are like a "thermal teleporter", and move the
heat from an area with restricted surface or volume, out into
a much larger array of fins. And for that purpose, they're great.
They allow an assembly with less mass to be used. One of the
nicer examples of the art, is the XP-120 - only 370g for a
massive assembly. This one doesn't have a tendency to torque
the motherboard, as it sits pretty close to the surface of
the motherboard. With a decent fan, theta_R is about 0.2C/W
or so. (The Zalman 9500/9700 series, is about 0.12 to 0.16C/W,
and are a bit better than that.)

http://www.thermalright.com/a_page/main_product_xp120_775.htm

http://www.silentpcreview.com/article186-page4.html

For comparison, an SLK800 with a Panaflo running at 12V,
is listed at 0.29C/W here. And yes, if you put enough of a
fan on it, you can probably get a better thermal resistance,
but at the price of extra noise. Which is the part of these
reviews that makes them hard to compare.

http://www.silentpcreview.com/article47-page6.html

HTH,
Paul
 
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