water cooling v. fan\heatsink

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I've been thinking about getting water cooling for my AMD 4200 X2, but
have been reading reviews that say they're only getting around 3 to 6
degrees lower than with fan\heatsink. My case has 5 80mm fans and one
smaller one (50mm, I think), not counting PS/CPU fans. I live in OR
where it does get hot (90 - 100+) in summer. CPU temp sits around 40C
idle. I'm a casual gamer.

Is water cooling worth the extra $$?
--
Biostar GeForce 6100-M9 939
AMD 4200+ X2
2 gigs Kingston ram
EVGA nVidia 7600GT PCI-E
450W PSU


Re: water cooling v. fan\heatsink



taragem:
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Probably not except it should be quieter than all those case fans. I used
to run a water setup and if you do it, cool everything (cpu, video, mb)
with water.



--
Mac Cool

Re: water cooling v. fan\heatsink




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Ok, thanks. Next question: I currently have a run-of-the-mill CPU fan/
heatsink (fan is smaller than 80mm). Would you recommend a beefier fan/
heatsink? For example: http://www.directron.com/amdopteronfan.html

Noise isn't a concern, unless it sounds like a buzz saw. I actually
like some fan noise as it acts like white sound and helps me sleep.

However, awhile back I ordered a cooler with a 120mm fan for an AMD 64
3000 and it literally sounded like a buzz saw and didn't make the CPU
run a bit cooler than the thermaltake heatsink with an 80mm fan that
was originally on there. I sent it back. There are so many different
designs I don't know what works and what doesn't.




Re: water cooling v. fan\heatsink



taragem:

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If you like white noise, there is a water set up that will produce both
white noise and cool better than fans or a typical closed water system and
that is an evaporative system. Rather than being enclosed and cycling
through a radiator and fan, you either trickle the water over a waterfall
or mist it through something like a shower head or pipe in which you've
drilled tiny holes. This was the type of system I ran when I did use water
cooling. You need to add swimming pool chemicals to the water to keep it
from getting slimy and a filter helps, but the chemicals are cheap.
Occasionally you will need to add water since the system is evaporative.
If you add a fan to the system, it's possible to cool the water below
ambient room temperature.

http://en.wikipedia.org/wiki/Cooling_tower
--
Mac Cool

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Thanks. Looks like a project I'd like to tackle. :)

Why did you stop using water cooling?



Re: water cooling v. fan\heatsink



taragem:

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When it came time to upgrade I was working about 60-70 hours/wk and I
bought a Dell because I didn't have time/desire to tinker anymore, been
using it now for several years. It's time to upgrade again and I have more
free time so I'm going to roll my own this time.

--
Mac Cool

Re: water cooling v. fan\heatsink



 > Thanks. Looks like a project I'd like to tackle. :)
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Have a look here for a review on the CoolIT freezone, it sounds reasonable,
and easy.

http://www.guru3d.com/article/processor/438 /



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Hey, that's cool - no pun intended. :) I think I'll wait until they
get the 'bugs' worked out like the fan, crimped hose (even though the
dude said there was no blockage -  I wonder over time if it would get
fatigued?) and make it a little more compact.



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I have one of these from Swiftech. A bit pricey, but not so much when you
consider the price of buying the parts seperately. It is very efficient too.
http://www.newegg.com/Product/Product.asp?Item=N82E16835108092&ATT=35-108-092&CMP=OTC-Froogle&cm_mmc=OTC-Froogle-_-Water+Cooling-_-Swiftech+Inc.-_-35108092


Ed



Re: water cooling v. fan\heatsink



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Actually, it is *not* very cool, in fact it produces a lot of *extra*
heat from the Peltier cooler.  These things work by passing a current
through a type of diode which causes one side of the diode to get hot
and the other to get cold.  But the efficiency is very poor.  IIRC, it
consumed two times the amount of heat being moved, so if it needs to
pass 50 watts from the CPU, it will draw 100 watts from the PSU and
output 150 watts to the air.  In my book, Peltier coolers are only for
very space constrained applications.

I would like to try to build a totally passive water cooled system.  I
thought about this a few years back when I built my last couple of
computers, but never finished it.  I used a cheap air cooled heatsink
and added plexiglass to enclose it.  I got 0.5" fitting mounted and
was ready to put it on a CPU.  That turned out to be the hard part.  I
would have had to make a special mounting bracket and got busy, so it
was never finished.

In order for this to work, I would have to use a very large radiator
mounted above the computer so that convection would cause the water to
circulate.  The large size of the radiator would provide lots of
cooling area eliminating the need for a fan.  I don't know for sure
how well this would work, but even if it is not cooler than a fan, it
will be nearly silent.  Only the PSU fan will be running.  It might be
possible to eliminate the PSU fan by using a passive chimney.  Then it
would be deadly silent with only the hard disk spinning.  Well, that
can be eliminated too by using Flash memory!

To help all this work I was thinking that one of the newer very low
power CPUs could be used like the BE-2350.  Seems when it is combined
with a 960 based mobo, it is very low power at idle and not very high
at full speed.

I don't know how practical all this is, but it would be the ultimate
in quiet!!!


Re: water cooling v. fan\heatsink



rickman:

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A good quality water pump is nearly silent. If you want to eliminate the
fans, go with an evaporative system like I described to the OP. I don't
believe you will get enough water movement through hoses using convection
to prevent the CPU from overheating. You would need a cylinder of water
sitting atop the CPU and some method, probably a fan, of cooling the water
as it rises.

--
Mac Cool

Re: water cooling v. fan\heatsink




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A. You don't need to restrain yourself to just water.
B. Use heat-pipe methods.

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Re: water cooling v. fan\heatsink



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Water is a pretty good coolant with a high specific heat and ready
availability.

How would a hobbiest work with heat pipes other than using a stock
heat sink incorporation heat pipes?  I was not aware that you could
construct your own heat pipes in any practical way.

Actually, wouldn't the design I described using convective movement of
water be pretty much like a heat pipe?  I guess the difference is that
the water never goes to the liquid phase... at least I hope not!

I did a little reading, and it looks like you could use Butane to form
a closed loop, passive two phase cooling system at just a little over
2 bar.  This would give a vapor temperature of about 25C.  Of course
it might be necessary to have a slightly higher working temperature to
make the radiator work effectively.  Pentane has a boiling point of 36
C which is higher than desired for cooling the CPU, but will make the
radiator more effective and not require a pressurized system.  Of
course both of these are flammable, but with Butane a leak would
quickly depressurize the system and the computer would alarm from an
over heat condition.  But clearly, this requires a lot more thought...



Re: water cooling v. fan\heatsink




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Heat-pipes are relatively simple devices.
A source of heat, a heat-sink, and a pipe or other connection between
them, a volatile liquid/gas in the device, with a capillary cloth or
material running from the sink to the source.

Water, while usable, is a fairly poor "volatile liquid" to use for a
heat-pipe.  You'd prefer a liquid that at "normal" pressure would easily
vaporize at the heat-source temperature; yet condense at the heat-sink
temperature (usually slightly above room-temperature).

There are many liquids that fill the bill:
Gasoline
Propane
Alcohol
Ammonia in water
Various refrigerant liquids.

People tend to shy away from the first three, even when used in a
completely closed device, because of their flammability, and the fourth
because of it's toxicity.  That's why Freons were invented (and used
today).

The basic design of a heat-pipe is very simple:
Heat boils a volatile liquid at one end, and it's condensed at the
other.  A relatively small cloth, rope, or other such item returns the
now-condensed liquid back to the heated end by capillary action.  No
moving parts except the liquid itself.

Yes, water *can* be used; as water *will* boil at reduced pressures.
The common and easiest way to do so is to partially fill the device with
the desired liquid (again, yes, water will do) and bring the *whole
device* to the boiling-point; expelling liquid, air, steam, and other
gas until only the desired liquid and it's gas (steam) is left in the
device; then seal it while still hot and before it starts to suck air
back in.

This can be used to produce "hand boilers" that boil water in the palm
of your hand from the heat therein.  Like I said, water *can* be used.

A person can make a demo of this with an old clear lightbulb and a
bunsen-burner.  Carefully remove the screw-base without breaking the
bulb.  Carefully either nip off, break off, or melt open the seal.  Heat
the bulb with a flame for a few seconds to drive out some of the air
inside; then stick the tip into a cup of distilled water; holding it
with a pot-holder so you hands don't get burned.  Take the bulb, now
about 10% filled with water, and place over the bunsen-burner in a rack.
Heat until the water is boiling furiously and you figure only steam is
coming out the nib.  Reduce heat, and seal.  To seal, the *preferred*
way is to melt the original nib closed with the bunsen-burner.  However,
wax or epoxy *can* be used if the demo isn't going to be permanent.

Let cool.  You'll now have a globe with a small amount of water in the
bottom that will actually *boil* in the palm of your hand from the heat
of your body, until the temperature equalizes.

A heat-pipe works the same way; except it has a heat-sink on the other
end taking away heat as fast as produced on the boiling end; with some
method of returning the liquid to the boiling end ... usually a small
bit of cloth or water-loving fabric that easily wets in the working
fluid.  However, in *some* systems where the heatsink is *always* above
the heat-source, gravity also works quite well.

http://www.cheresources.com/htpipes.shtml
http://technology.grc.nasa.gov/tops/TOP300155.pdf
http://electronics-cooling.com/articles/1996/sep/sep96_02.php

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The transfer is nowhere near as efficient as a heat-pipe.
In a really good heatpipe design, the temperature difference between
heatsink end and heat-source rivals or even sometimes beats pumped
liquid designs; but without the problem of pumps, seals, and extra heat
input by the pump itself.  Also not energy source other than the heat
differential itself is needed to power the device.
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Butane, pentane, propane, all make good working liquids for that
temperature-range.  Water *can* be used (see above); but it's "normal"
heat-of-vaporization isn't ideal for the job.  Some people though get
scared when working with flammables like those.

OTOH, the machinery to work constantly with freons these days and not
let waste escape to the atmosphere, get rather expensive.  (Ask any
air-conditioning auto-mechanic.)

As for a "pressurized system": ALL such systems are pressurized, or at
least SEALED so that there's nothing inside but the desired liquid and
its gas.  At whatever temperature you work it at, the liquid/gas *will*
reach equilibrium, where additional heat will cause some of it to boil,
while reducing or removing heat will cause some to condense.  That's how
the system works.

And work it will, no matter what the working-fluid, over a *wide* range
of temperatures.  Even water.  The only worry being:
A. Freezing of the working liquid.
B. Not enough liquid vaporizing fast enough.
C. The working pressure getting too high for the design.

A. In this design is something you won't have to worry about.
   (If it freezes, nothing is damaged.)
B. This is where your choice of liquid/gas is chosen.
C. You need to make sure you have a big enough heatsink to keep the
temperature low enough that this doesn't occur.

Finally, you want to make sure your wick and distance run *can* return
enough liquid to the high-end fast enough; or you'll have the source
boiling away all the liquid faster than it can return; with all the
liquid at the heatsink end and only gas at the source (back to your
original convective design) ... a definite no-no for a CPU cooler.

Gravity as a backup helps a lot.

However, when properly designed, heat transfers from source to sink of a
heatpipe with almost unbelievable efficiency; and pretty much at the
speed of sound.  It's *almost* a heat-superconductor.  Almost.

Like stated above though, that does you no good if your heatsink isn't
big enough to cool the device.  All a heatpipe does is *transfer* heat
(like a watercooled device) not get rid of it.  You still need a nice
large external heatsink for that.  The bigger the better.

You just don't need to have it sitting right on top of the CPU any more.

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 (_/   / (_(_/|_/ / <_/ <_

Re: water cooling v. fan\heatsink



Frank McCoy:

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Are you using one like you describe on your computer?

--
Mac Cool

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Hell no!
WAY too expensive.
My fan-cooled heatsink keeps my CPU at a comfortable 47C and my chassis
is at an even cooler 40C.  Why would I put a huge device like a heatpipe
in a system working that well?

If I was building a super-dooper Gaming machine with quad processors
pulling 75 watts, I might think of such as being preferable to a water
cooled and pumped device.  It would be more efficient, quieter, and
simpler; though probably not cheaper.

SOME motherboards actually come with heatpipe devices built in/on.
But usually that's for the fancy chipset, not the CPU.

--
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  ,-/-, __  __.  ____  /_
 (_/   / (_(_/|_/ / <_/ <_

Re: water cooling v. fan\heatsink



A watercooling setup will dissipate heat from simple convection current of
the water through the pipes.  I demonstrated this on mine by turning off the
pump and fans, and running the system at an underclocked speed.

Cpus temps hovered fairly high, upper 50s, but usable, and the large
external car oil cooler I used was definitely getting warm, so convection
was definitely occurring.  I ran the system like this for a couple of years,
turning the pumps/fans back on when overclocking for gaming.

An improved setup designed to encourage convection might work quite well.
Some company does produce a very tall radiator device but I believe it still
incorporates a pump.

rms



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That is what I have thought.  By definition a convection system will
have a higher temperature drop since it is the temperature drop that
drives the heat flow.  In a pumped system the heat in the liquid is
pushed along by the pump.  The other parts of the system still
passively conduct heat however.  The heat flow from the CPU through
the heatsink to the liquid is passive.  The flow from the liquid
through the radiator to the air is still passive.  The flow from the
air around the radiator to the bulk of the air in the room is either
passive or with a fan is now driven.  Driven heat flows can approach
zero degree temperature drop, limited only by the speed at which the
medium can be pumped.  But the temperature drops across the passive
portions of the heat path will not change.

In a totally passive system the resistance to heat flow should be
reduced by using large, open pipes or advanced technologies such as
heat pipes (if practical).  One that I would like to try out sometime
is a chimney on the PSU instead of a fan.  A six inch tube perhaps 5
foot high should provide an adequate air flow equivalent to an 80 mm
fan at low RPM.  That should be easy enough to test.  Maybe I'll try
that later today...  I need to go to the hardware store anyway.




Re: water cooling v. fan\heatsink



Frank McCoy:

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That's what I guessed. Basically you're just writing to show off
irrelevant knowledge of heat pipes.

--
Mac Cool

Re: water cooling v. fan\heatsink



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http://www.cheresources.com/htpipes.shtmlhttp://technology.grc.nasa.gov/tops/TOP300155.pdf
http://electronics-cooling.com/articles/1996/sep/sep96_02.php
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It seems to me that I asked you what time it was and you told me how
to build a watch!  Maybe that is not a good analogy, because I asked
you how a hobbiest could build a heat pipe and you gave me tons of
background info, but nothing useful in building a practical heat pipe
system.

My discussion of working fluids was in the context of the convection
liquid cooled system.  If it could be done by forming vapors, as is
done in a heat pipe, then it will work pretty much the same.  One pipe
from the CPU block will collect and carry away the vapors and the
other will return the liquid to the CPU block.

The problem with trying to make a heat pipe is that the construction
is difficult.  I have never heard of anyone making one themselves.  If
you know a practical way of doing this, I would be very interested.


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