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(NVIDIA) Fan-Based-Heatsink Designs are probably wrong. (suck, don't blow ! heatfins direction)

 
 
Skybuck Flying
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      08-18-2012, 05:19 PM
Hello,

I am starting to believe that NVIDIA's Fan-Based-Heatsink Designs like the
recent GTX 690 are totally wrong !

And here is why:

The heatsink fins are placed in the same direction as the airflow. This will
cause dust to easily get stuck between the heatsink fins and especially in
front of it.

THIS IS WRONG. This will cause the heatsink to get full of tiny little hair
pieces and dust particles.

HERE IS HOW TO RESOLVE/IMPROVE THE SITUATION:

Place the heatsink fins 90 degrees turned so that the overflow must go OVER
the heatsink fins and not in between.

So here is a picture to show the wrong situation and the better situation:

top view of card when place on table:

1. WRONG DESIGN:

HEATSINK FINS:

---------------------
------------------------
+-------+
--------------------- <----- airflow | FAN
<--airflow--- -----------------------
+-------+
---------------------
-----------------------

2. BETTER DESIGN:

| | | | | |
|
| | | | +------+ | | |
| | | | <---- airflow | fan | <--- airflow | | |
| | | | +------+ | | |
| | | | | | |


This better design should hopefully and be designed in such a way... that
air/heat GETS sucked out of the heatfins by blowing air OVER IT and not in
between... to reduce the chance of stuff getting stuck in it !

So there should be some room OVER the heatfins to be able to blow air
through it.

Bye,
Skybuck.

 
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Skybuck Flying
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      08-18-2012, 05:26 PM
Additional:

Since my horror experience with the 7900 gtx cards I am afraid to buy
graphics cards with the nvidia heatfins direction.

I am afraid that the graphics cards heatsink fins will get full of dust and
stop to function !

My newest passively cooled graphics card is actually also an nvidia/asus
design. Where the heatfins are in the direction against the airflow.

So far there is probably no dust in side of it... or very little... which
seems to be much better.

If nvidia wants my bussiness back they will have to design cards which can
operate for the long term, without requiring any cleaning what so ever.

I am not going to open up my PC and risk damage during cleaning operations.

NO CLEANING operations should be necessary.

THEREFORE nvidia must design graphics cards which will operate for a long
time... 5 to 10 years of blowing/sucking air.

Perhaps the heatfin direction that I proposed is less optimal in the short
term... but will probably be optimal in the long term.

Therefore my advise to nvidia which they hopefully already have:

1. BUILD A DUST/PARTICLE LAB.

2. TEST the graphics card heatsink design for as long as possible... and
test the situation with dust build up.

3. Build the graphics cards which has the least problems with dust build up.

Otherwise you can go to hell... I do not ever want to face overheating
problems because of gpu overheat/heatsink full problems !

Bye,
Skybuck.



 
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Skybuck Flying
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      08-18-2012, 05:36 PM
One last explanantion/addition for any potential dumbos out there to explain
the "suck, don't blow" part of the title.

The idea is to:

BLOW air OVER heat fins.

Hopefully this will create some kind of suckage effect over the heatfins and
suck heat from between the heat fins and blow it away.

This might also have a beneficial effect of sucking any dust/hair particles
out of it and blowing it out.

That's the idea at least... which would be very nice.

I am not sure if it will work like that in practice... since there is no
opening on the other side of the heat fin to suck from....

So maybe some kind of vacuum would result from it...

If that is a good or bad thing remains to be seen/tested.

Very maybe openings could create on the other side... but that would
probably start to suck dust between the fins which would be bad.

So experimenting with this idea is required to see what works best long
term.

My only worry would be that the opposite might happen, maybe dust will start
to fall down between the heatfins....

What will happen in reality I don't know...

THIS REMAINS TO BE TESTED ! =D

Perhaps someday... a dust particle simulator might show what happens

Bye,
Skybuck

 
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MrTallyman
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      08-18-2012, 07:18 PM
On Sat, 18 Aug 2012 19:19:11 +0200, "Skybuck Flying"
<(E-Mail Removed)> wrote:

>
>I am starting to believe


You are an idiot.

They suck so that YOU still have direct access to clean the tines of
the heat sink. If they blew, the heat sink would get plugged up in a
place under the fan, and you would have to remove the fan to clean it.

Now shut up and go away and stop making posts which you are then the
only idiot who responds to it the first 5 times!

Grow up, child! You are immature AND stupid. Get over it. Leave US
out of it.

You are a very particular type of Usenet idiot, and you are blind to
it.
 
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John Larkin
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      08-18-2012, 07:59 PM
On Sat, 18 Aug 2012 19:19:11 +0200, "Skybuck Flying"
<(E-Mail Removed)> wrote:

>Hello,
>
>I am starting to believe that NVIDIA's Fan-Based-Heatsink Designs like the
>recent GTX 690 are totally wrong !
>
>And here is why:
>
>The heatsink fins are placed in the same direction as the airflow. This will
>cause dust to easily get stuck between the heatsink fins and especially in
>front of it.
>
>THIS IS WRONG. This will cause the heatsink to get full of tiny little hair
>pieces and dust particles.
>
>HERE IS HOW TO RESOLVE/IMPROVE THE SITUATION:
>
>Place the heatsink fins 90 degrees turned so that the overflow must go OVER
>the heatsink fins and not in between.
>
>So here is a picture to show the wrong situation and the better situation:
>
>top view of card when place on table:
>
>1. WRONG DESIGN:
>
>HEATSINK FINS:
>
>---------------------
> ------------------------
> +-------+
>--------------------- <----- airflow | FAN
><--airflow--- -----------------------
> +-------+
>---------------------
> -----------------------
>
>2. BETTER DESIGN:
>
>| | | | | |
>|
>| | | | +------+ | | |
>| | | | <---- airflow | fan | <--- airflow | | |
>| | | | +------+ | | |
>| | | | | | |
>
>
>This better design should hopefully and be designed in such a way... that
>air/heat GETS sucked out of the heatfins by blowing air OVER IT and not in
>between... to reduce the chance of stuff getting stuck in it !


And reduce the chance of getting heat out of it.

Even better, aim the fan at something else a foot or two away.

You are of course assuming that you know more about cooling a CPU than
all the people who currently make a living cooling CPUs, including the
MEs in charge of thermal design at Nvidia.


I have this theory that the fins of a heat sink should reduce a fan's
free-flow rate by 50% for optimum heat transfer.


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
 
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Flasherly
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Posts: n/a
 
      08-18-2012, 11:33 PM
On Aug 18, 3:59 pm, John Larkin
<(E-Mail Removed)> wrote:
>
> I have this theory that the fins of a heat sink should reduce a fan's
> free-flow rate by 50% for optimum heat transfer.


Unless chambered to stop air flowing in for an arbitrary 10-25%
reduction of motor shaft speed, equal to chambering outflow, or both
chambered, as opposed to an effective vacuum, which might further
indicate where motor design is outside operational efficiency,
irrelevant of equipment MTBF, and provided there's salience to some
residual mean temperature for cooling to be a factor in coincident
significance to ascribe at the proposed structural end as an operative
upon RPM.
 
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Rheilly Phoull
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      08-18-2012, 11:57 PM
On 19/08/2012 7:33 AM, Flasherly wrote:
> On Aug 18, 3:59 pm, John Larkin
> <(E-Mail Removed)> wrote:
>>
>> I have this theory that the fins of a heat sink should reduce a fan's
>> free-flow rate by 50% for optimum heat transfer.

>
> Unless chambered to stop air flowing in for an arbitrary 10-25%
> reduction of motor shaft speed, equal to chambering outflow, or both
> chambered, as opposed to an effective vacuum, which might further
> indicate where motor design is outside operational efficiency,
> irrelevant of equipment MTBF, and provided there's salience to some
> residual mean temperature for cooling to be a factor in coincident
> significance to ascribe at the proposed structural end as an operative
> upon RPM.
>


Umm, you would not perchance be employed in a government position (spin
doctor) ??
 
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Robert Macy
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      08-19-2012, 12:19 AM
On Aug 18, 12:59*pm, John Larkin
<(E-Mail Removed)> wrote:
> I have this theory that the fins of a heat sink should reduce a fan's
> free-flow rate by 50% for optimum heat transfer.
>


optimum heat transfer? not sure what the criteria would be, but think
instead about the air's thermal mass, thermal resistance form metal to
bulk air. and you see you're left with characteristics of the heat
sink, not the characteristics of the fan.

As a mind argument enfisionone hell of a powerful fan. Now block that
to half flow, what do you have? versus an 'underpowered' fan that is
blocked to half flow. .
 
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DK
Guest
Posts: n/a
 
      08-19-2012, 12:31 AM
In article <(E-Mail Removed)>, John Larkin <(E-Mail Removed)> wrote:
>
>You are of course assuming that you know more about cooling a CPU than
>all the people who currently make a living cooling CPUs, including the
>MEs in charge of thermal design at Nvidia.


When a video driver installation takes 200 MB on a hard drive
and is still full of bugs, there is every reason to question designers'
competence.

DK


 
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Quadibloc
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Posts: n/a
 
      08-19-2012, 12:54 AM
On Aug 18, 11:19*am, "Skybuck Flying" <(E-Mail Removed)>
wrote:

> Place the heatsink fins 90 degrees turned so that the overflow must go OVER
> the heatsink fins and not in between.


The reason the heatsink _has_ fins is to maximize the contact area
between the heatsink and the air. So you also want to maximize the
velocity of the air in proximity to every part of the heatsink, so
that there is a larger temperature difference over as much of that
large contact area as possible.

One puts a dust filter in front of the intake vent to keep dust out of
the fins, although dust generally does not collect where there is a
violent wind.

What you really want to do, though, is use a working fluid other than
air which can carry more heat away. Of course, the Montreal Protocol
because of the ozone layer makes that more complicated; the other
alternative requires careful precautions because it becomes
electrically conductive very easily by dissolving material.

But a third alternative to setting up a refrigeration system and using
chilled water would be using chilled mineral oil. Of course, there,
flammability is a problem, although the fractions typically used for
such purposes aren't too bad...

John Savard
 
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