I have two units with after market hsf one pushes air down through the heatsink, the other pulls air up through it. i thought I'd make them both the same but not sure witch is most efficent.

I don't think I have ever seen a heatsink with a fan pulling air through it as opposed to pushing it. Do you have a link to a picture of this thing? The problem I see with pulling air out is that I think it would tend to suck air from the outside directly to the fan, creating a vacuum in the middle where there would be very little air flow and therefore very little cooling. If the heatink is designed differently, it could work but as I said I have never seen such a thing.

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A member of The Knights Who Say NI!
For rankings, history graphs and more, check out:
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> but not sure witch is most efficent.

Let me put it this way. Where would you expect to feel coolest - standing in front of a fan or behind it? ;)

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Be lucky

Neil

These are very common hsf's i think one of the fans is either wired wrong or was installed upside down. I removed one and washed the heatsink, then replaced as was.My temps droped from 57 to 43, so I guess untill I get a defenitive ans. I'll leave alone.

> I don't think I have ever seen a heatsink with a fan pulling air through it as
> opposed to pushing it. Do you have a link to a picture of this thing? The
> problem I see with pulling air out is that I think it would tend to suck air
> from the outside directly to the fan, creating a vacuum in the middle where
> there would be very little air flow and therefore very little cooling. If the
> heatink is designed differently, it could work but as I said I have never seen
> such a thing.
>
>
> I dont know if this is what this guy has but here is links to some heat sinks with double fans.
>
>http://www.xoxide.com/dp102.html
>
>http://www.xoxide.com/insoc42pen4c.html
>
>
> I have bought several of these heatsinks and they all work better than stock.

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A great majority of heatsinks work best with the fan blowing into them. Usually if the fan comes from the factory sucking though, it was designed for most efficient airflow that way (I believe some Alpha HSFs suck, and were designed with this in mind). The only way to know which is most efficient would be to try it both ways, keeping an eye on the temperature. Whichever has the lowest temp you'll want to use ;)

In practice I haven't really noticed much of a difference either way to be honest. My HS (which may be an exception) seems to perform equaly well (to 1 degree Celcius anyway) with the fan sucking or blowing.

Puffy

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> ...
> I believe some Alpha HSFs suck, and were
> designed with this in mind...

Yes, you are right, cause i have an 6035 Alpha on
an Athlon 1400 and it is right this way (sucking air)
from the heatsink. I tri'ed the other way around...
but the suggested way (sucking air) is just right!!!
so do'nt fuzz around, if your manufacturer suggested
that sucking is right...

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Aloha, Uli

And I wonder which would collect more dust? Intuition tells me the fan that sucks would have more of a dust problem, but......?

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<img src='http://www.boincsynergy.com/images/stats/comb-912.jpg'>

> > I don't think I have ever seen a heatsink with a fan pulling air through
> it as
> > opposed to pushing it. Do you have a link to a picture of this thing?
> The
> > problem I see with pulling air out is that I think it would tend to suck
> air
> > from the outside directly to the fan, creating a vacuum in the middle
> where
> > there would be very little air flow and therefore very little cooling.
> If the
> > heatink is designed differently, it could work but as I said I have never
> seen
> > such a thing.
> >
> >
> > I dont know if this is what this guy has but here is links to some heat
> sinks with double fans.
> >
> >http://www.xoxide.com/dp102.html
> >
> >http://www.xoxide.com/insoc42pen4c.html
> >
> >
> > I have bought several of these heatsinks and they all work better than
> stock.
>

[OFF-TOPIC]
Might help if you wouldn't put quote marks in front of your own reply.
[BACK ON-TOPIC]

L8R....

My Time: Saturday, 12 February 2005 - 06:49 PM --800 (Pacific Standard Time)

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CAPT Siran d'Vel'nahr - L L & P _\\//
Winders 11 OS? "What a piece of junk!" - L. Skywalker
"Logic is the cement of our civilization with which we ascend from chaos using reason as our guide." - T'Plana-hath

> And I wonder which would collect more dust? Intuition tells me the fan that
> sucks would have more of a dust problem, but......?
>

If the fan blows, it would suck in dust, etc from other places in the case...

If the fan sucks, it would distribute dust from the air exiting other places in the case.

either way, dust build up (airflow into the case is the same in either fan direction!)

it's 6 of one, 1/2 doz of the other....

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And, be sure to clean out the box inards now and then. I built mine about 8 months ago and the other night, the CPU/MB monitor sounded an alarm of overheating. Shut down, pulled covers, got out the air-in-a-can and found the heatsink fins clogged with dust. Blew everything out and it dropped the temp about 20° C.

L8R....

My Time: Saturday, 12 February 2005 - 07:02 PM --800 (Pacific Standard Time)

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CAPT Siran d'Vel'nahr - L L & P _\\//
Winders 11 OS? "What a piece of junk!" - L. Skywalker
"Logic is the cement of our civilization with which we ascend from chaos using reason as our guide." - T'Plana-hath

If you have pets or smoke, you need to clean the insides more often.

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Now think about it from a scientific point of view. Cold air is denser then hot, so if the fan were rotating with the same speed in both cases, you would move more atoms with each rotation if you push the air, but you would need more energy because the mass is greater. If you push the air the energy converted into heat by running the fan would blow over the CPU. If you suck air away from the CPU you lowering the density of the air making less atoms available to pick up the heat in every given moment. Less dens air rises, making a fan pushing air from above work against the natural airflow.

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> > And I wonder which would collect more dust? Intuition tells me the fan
> that
> > sucks would have more of a dust problem, but......?
> >
>
> If the fan blows, it would suck in dust, etc from other places in the case...
>
> If the fan sucks, it would distribute dust from the air exiting other places
> in the case.
>
> either way, dust build up (airflow into the case is the same in either fan
> direction!)
>
> it's 6 of one, 1/2 doz of the other....
>
You may be right, but I would assume dust would tend to come into the heatsink from the side in one case and be direceted to the center in the other. So the proper design of the fins and the direction of airflow could enhance a heatsink.

I've got two computers in the same room with the same cases. One has the cheap heatsink that came boxed with the AMD processor; the other has a more expensive heatsink and it needs far less cleaning.

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<img src='http://www.boincsynergy.com/images/stats/comb-912.jpg'>

> I have two units with after market hsf one pushes air down through the
> heatsink, the other pulls air up through it. i thought I'd make them both the
> same but not sure witch is most efficent.
>

I prefer to have the fan blowing down on the heatsink. I've tested this myself before, and when the fan blows down on the heatsink, it's cool to the touch. If it sucks air, then the heatsink warms up. Dust isn't a problem if you use compressed air once a month or so.

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You will be assimilated...bunghole!

> Dust isn't a problem if you use compressed air once a month or so.

I prefer to use a vacuum cleaner and paintbrush. At least I know then that dust isn't being blown into some other critical place. ;)

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Be lucky

Neil

> I've got two computers in the same room with the same cases. One has the cheap
> heatsink that came boxed with the AMD processor; the other has a more
> expensive heatsink and it needs far less cleaning.
>

"if the MB isn't gray and fuzzy, it's not been broken in, and if it is gray and fuzzy, it's time to upgrade!"

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> "if the MB isn't gray and fuzzy, it's not been broken in, and if it is gray
> and fuzzy, it's time to upgrade!"
>
So you are rich enough to replace your motherboard when it gathers dust? I figured as much! You don't really add much to these discussions by trying to tell everyone how much you know and how everyone else is wrong.

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<img src='http://www.boincsynergy.com/images/stats/comb-912.jpg'>

> > ....
> "if the MB isn't gray and fuzzy, it's not been broken in, and if it is gray
> and fuzzy, it's time to upgrade!"
>

Now that's a way of looking at it I hadn't thought of.

L8R....

My Time: Sunday, 13 February 2005 - 05:04 PM --800 (Pacific Standard Time)

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CAPT Siran d'Vel'nahr - L L & P _\\//
Winders 11 OS? "What a piece of junk!" - L. Skywalker
"Logic is the cement of our civilization with which we ascend from chaos using reason as our guide." - T'Plana-hath

> > "if the MB isn't gray and fuzzy, it's not been broken in, and if it is
> gray
> > and fuzzy, it's time to upgrade!"
> >
> So you are rich enough to replace your motherboard when it gathers dust? I
> figured as much! You don't really add much to these discussions by trying to
> tell everyone how much you know and how everyone else is wrong.
>

You're being a jerk.. It was a joke!

Replaced my main Pent pro just a year back, and it was fuzzy! I smoke and have cats!

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