Blowing air between the hs and cpu..

[Guest]

Just a thought but id imagine that if you had a fan with a funnel on it to force air between the hs and the surface of the cpu that isnt in contact with the hs, Would lower the cpu temp quite a bit by cooling the processor package..
Anyone tried this??

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[Grizely1]

No that wouldn't cool as good as if you were blowing air on the heatsink. the whole point of a heatsink is to cool better than just blowing it on the normal surface area. The heatsink increases surface area thereby making the temperature lower. The heatsink pulls heat away and out of the cpu, and the fan just gets it off the heatsink. if what you said would work than why do you think we have heatsinks?

 

[mpjesse]

That's a BAD idea. The purpose of a heatsink is to spread the heat over a large area. Even that vapochill system uses a heatsink.

-MP Jesse

 

[Crashman]

Now if you instead were to use a funnel to blow air from a much larger fan onto the heatsink, that would work.

Suicide is painless...........

 

[phsstpok]

I think evolution is talking about blowing air around the core. The heatsink sits atop the core but there is gap between heatsink and the ceramic package. However, that is very small space in which to attempt to blow air.

 

[Guest]

Yeh like when the hs is on the cpu there is a gap between the parts of the hs that are not in contact with the core and the rest of the processor package so surely blowing air through here would assist in cooling by lowering the ambient temp around the package..
Id imagine that in a normal setup that the air between the hs and package would be rather warm, and hence keeping the processor warm.

thanks phsstpok.. some 1 understands my terrible explination

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[yoda271828]

Adding that fan wouldn't hurt, but I wouldn't expect it to add much too the cooling effect.

 

[Guest]

If i get my hands on a decent thermocouple il give it a try and post the results, I wonder if anyone else has tried this?
Iv noticed people sayin that copper shims are used to cool the processor package(as well as protect the core) but id imagine this would be better..

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[Guest]

isn't the point of thermal compound to close this air gap and efficiently transfer heat from the cpu to the heatsink which can dissipate it?

 

[Guest]

Just to settle this once and for all...
You mount the hs to the processor using normal methots, i.e. heat transfer compound between the hs and the core!!

When the hs is mounted thus there is a gap between the flat plate of the hs and the processor package. Due to the fact that the core sits proud of the rest of the package(and the hs sits on the core!)
It is in this gap that i am sujesting air be blown..

Soz this isnt a dig at u spetzo, Its my own fault for not explaining clearly enough ;o)
Hope that clears it up!

******
My other sig is thought provolking and interesting.(And spelt corectly)

 

[Guest]

why dont you drill small holes in the bottom of the heat sync? that would accomplish what you are tring to do if i am not mis-understanding what it you are tring to do.

 

[Guest]

Well that would reduce the mass of the hs and hence its ability to absorb heat, thats a really good idea...
But what i am sujesting (i.e.using a funnel) would force cold air through that gap really fast, increasing the cooling effect tho ur idea is slightly more practical!

******
My other sig is thought provolking and interesting.(And spelt corectly)

 

[Grizely1]

isn't the point of thermal compound to close this air gap and efficiently transfer heat from the cpu to the heatsink which can dissipate it?

No...... IF that was true you would have to buy about $100 worth of thermal compound. Thermal compound <i>actually</i> isn't that thermal (compared to metal, anyways). You put it between the core and the heatsink (not too much thermal compound though. like a paper thin layer). It's designed to fill in the microscopic gaps between the heatsink and core for better heat transfer.

 

[Guest]

I put one of those case fans above the North Bridge, and blowing towards the CPU...
The temperature reported by my A7V dropped around 5-8C... however, I'm not sure whether that was because the air was really cooling off the CPU, or whether the air was getting under the socket and blowing on the thermistor...

 

[Grizely1]

well your probe is screwed cause 5-8c using air cooling is impossible unless you're outside and it's winter. The lowest you can get is room temp (probably like 24c or something).

 

[Ncogneto]

I understand what you are trying to accomplish and do not think it is worth the effort. First of all you will only be cooloing the silicon and not the core. If you are concerned about this air pocket you can however purchase a copper shim that has a cutout for your core and effectivly eliminates this dead space. It will increase your surface area of the cpu to heatsink. Typically you may see a drop in temp of about 1c maybe 2c if your lucky. this will be more effective than trying to engineer a funnel ( the back pressure caused by such a device would hardly allow any airflow thru the small end of the funnel anyways.)

A little bit of knowledge is a dangerous thing!

 

[Grizely1]

OH nevermind I understand now. It droped 5-8c, not dropped TO 5-8c.

 

[Guest]

Air will not conduct heat as well as the thermal compound, so I don't think you can blow air onto the heat sink and effectively use the air to transfer the heat.

 

[Guest]

Drilling holes in the heat sink could work, but I guess it would only work in places where the sink is not touching the CPU. But then again drilling anywhere I guess decreases the surface area in direct contact with the CPU.

 

[Guest]

Drilling holes in the heat sink could work, but I guess it would only work in places where the sink is not touching the CPU. But then again drilling anywhere I guess decreases the surface area in direct contact with the CPU.

I assume you mean drilling holes on in the surface contacting the CPU? Or elsewhere on the CPU?

 

[Guest]

Why would you want to reduce the ability of the sink to absorb heat? I thought the less heat it absorbs, the less heat you draw away from the CPU and hence the less heat you dissipate.

 

[Guest]

Am I correct in assuming that the transfer of heat between air and metal is considerably less efficient than the transfer of heat from metal to air? Hence, you don't want to decrase mass you want to increase surface area, such that the sink contacts as much air flow as possible?

 

[TheSandman]

Mike01 are you on crack? Or have you not read any of the posts? Yes the area of concern is between the PACKAGING of the cpu and the heat sink. Surface area is more inportant than mass but the two generaly go handinhand ie more surface=more mass. If he were to drill small holes in the heat sink around the core the loss in mass would have very litle affect if any while the airflow to the gap would remove stagnant air that just holds heat. But what he has done as stated in an earlier post has reduced temp by 5-8c.

SANDMAN

 

[Crashman]

Duhhh, lets see. The heatsink is mounted to the CPU using thermal compound. A fan on top of the heatsink moves air across it's surface and transfers heat away from the heatsink, which in turn transfers heat away from the CPU. Now. 2 things affect the cooling affect on air on the heatsink-suface area and airflow. By increasing airflow you increse the amount of heat that can be exchanged, rducing suface temperature of the heat sink. The heatsink is mounted to the CPU using thermal compound. If you use a larger fan you increase cooling affect by increasing airflow. But when the fan becomes BIGGER than the heatsink, you can use a FUNNEL to direct the airflow over the haetsink. That is to say you could use a 16" box fan and a funnel of apropriate size to increase airflow. This has nothing to do with thermal compound, as the heatsink is still mounted in the normal fashion USING compound. His idea was originally to force air into the small gap between the Pin-Grid Array and the Heasink. You see, the processor die sticks out from the pin-grid array by a small distance, so with perfect contact of the processor to the die, using thermal compound to fill the gaps, there is still a small gap all the way around the die. In case your still not following me or him, this is the place where you would put a shim if you wanted, the place where AMD processors have the little felt pads located. So while he suggested that he might blos compressed air into the space, effectively using the pin-grid array as a thermal conductor, I suggested that he would be better off to leave it mounted normally and increase his fan size.

Suicide is painless...........

 

[Lowlypawn]

WOW, I would have never thought this would turn into such a long thread.
I had an Idea to modify my heat sink ( a copper hedgehog )and want your guys opinion.

First u know the side of the heat sink where it’s flat before the fins come out.
I was thinking of machining little groves about ¼ of an inch deep to create little fins on the side.
Maybe with a dermel.

Side view

!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!! < Fins
!!!!!!!!!!!!!!!!!!
OOOOOOOO
OOOOOOOO < Cut groves here on all 4 sides
OOOOOOOO
____XX____ < CPU

My other Idea would be to take off the heat sink and look where the Thermal paste was.
Then cut grooves to leave little fins or drill holes everywhere except where the CPU goes.

Bottom of heatsink

OOOOOOOOO O = Heatsink
OHOHOHOHO
HOHOOOHOH H = Hole or grooves ¼ inch deep
OHOXXXOHO
OHOXXXOHO X = CPU
OHOXXXOHO
HOHOOOHOH
OHOHOHOHO
OOOOOOOOO


My theory is to create more surface area the just a flat surface that’s normaly there.
Thus hopefully drawing away more heat.

Let me know what u think.
Thx & Cya