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Think sliding a copper slug between the GPU and HSF of my 6600GT will help much ?

D

Dazed and Confused

Banned
I have an engineering sample XFX 6600GT that I'm going to be volt modding here shortly and was just wondering if u guys think it'd b worth putting a lapped 1/8" copper slug between the Alu HSF of the 6600GT and the GPU. I haven't actually lapped the HSF yet but will be doing so shortly when I rip the thing out to volt mod it.

The Copper slug was nicely lapped about a month ago so it's ready to be used once I take it off the Socket A HSF it's on now. Sadly I can't use the whole HSF as the 6600 is in a Q-Pack and has a Wireless Pci card 1 slot awat ( 6600GT ) ( Empty Pci slot ) ( Wireless card )

Temperature log :

Before lapping Alu heatsink with pre existing lightly lapped copper slug with stock GPU voltage ( arround 1.36v ) : 53* idle

After lapping Alu heatsink and Vmodding GPU to 1.48v without any copper slug : 56*idle

After adding the 1/8" highly lapped copper slug to the mix while keeping the 1.48v GPU mod intact, the idle temp went from 56*C to teetering on 54/55 *C @ idle 🙂

-------

Omfg sauce, I'm now @ 4446 points running 590/1298 on 3DMark05 since adding the copper slug ROFL.

 
Originally posted by: Dazed and Confused
I have an engineering sample XFX 6600GT that I'm going to be volt modding here shortly and was just wondering if u guys think it'd b worth putting a lapped 1/8" copper slug between the Alu HSF of the 6600GT and the GPU. I haven't actually lapped the HSF yet but will be doing so shortly when I rip the thing out to volt mod it.

The Copper slug was nicely lapped about a month ago so it's ready to be used once I take it off the Socket A HSF it's on now. Sadly I can't use the whole HSF as the 6600 is in a Q-Pack and has a Wireless Pci card 1 slot awat ( 6600GT ) ( Empty Pci slot ) ( Wireless card )
Click to expand...

for all the work why dont you just replace the heat sink to something better.
 
Okay, copper disperses heat more evenly than Aluminum. In other word the heat transfered to aluminum never goes far from the contact source, so the entire surface never gets fully utilized, when you add copper to the mix the heat is more evenly distributed along a broader area.

In this case a copper slug should theoretically transfer heat to a larger area of the Alu heatsink so that the Alu heatsink can then disperse the heat more effeciently. This is the whole idea of a copper core in HSF's and I guess I kinda answered my own question now didn't I ?

Copper slug between the soon to be lapped Alu heatsink and GPU it is 🙂 With plenty of Arctic Ceramique between the copper and the HSF I should actually gain thermal performance and maximize heat dissipation 😀
 
Originally posted by: Dazed and Confused
Okay, copper disperses heat more evenly than Aluminum. In other word the heat transfered to aluminum never goes far from the contact source, so the entire surface never gets fully utilized, when you add copper to the mix the heat is more evenly distributed along a broader area.
Click to expand...
Copper has a lower thermal resistance compared to Aluminum.
In this case a copper slug should theoretically transfer heat to a larger area of the Alu heatsink so that the Alu heatsink can then disperse the heat more effeciently. This is the whole idea of a copper core in HSF's and I guess I kinda answered my own question now didn't I ?
Click to expand...
You are ignoring the interface between the copper and aluminum. You can never get a low thermal resistance between copper and Aluminum using thermal paste. The sinks you are talking about have a very good contact between the copper and Aluminum part of the sink.
Copper slug between the soon to be lapped Alu heatsink and GPU it is 🙂 With plenty of Arctic Ceramique between the copper and the HSF I should actually gain thermal performance and maximize heat dissipation 😀
Click to expand...
Again, you are ignoring the relatively high thermal resistance of the thermal paste. Thermal paste is only better than air. But, it is much worse than Aluminum.
 
Originally posted by: Dazed and Confused
For all the work I save $$$ vs spending more $$$ that I don't want to spend on video atm.
Click to expand...


I think you could get an artic cooling VGA cooler for your card for like $15. I think those have a copper base

EDIT: you can this AC NV silencer (yes it has a copper base) for $10 here
 
Originally posted by: Navid
In this case a copper slug should theoretically transfer heat to a larger area of the Alu heatsink so that the Alu heatsink can then disperse the heat more effeciently. This is the whole idea of a copper core in HSF's and I guess I kinda answered my own question now didn't I ?
Click to expand...
You are ignoring the interface between the copper and aluminum. You can never get a low thermal resistance between copper and Aluminum using thermal paste. The sinks you are talking about have a very good contact between the copper and Aluminum part of the sink.
Click to expand...

Precisely. Adding another interface can decrease cooling performance.
 
I'm sitting at 53*C idle atm. I'll try it with the lapped copper slug and the lapped Alu HSF first and recheck temps. Then I'll try it without the slug and we will all know for sure.
 
Originally posted by: Dazed and Confused
I'm sitting at 53*C idle atm. I'll try it with the lapped copper slug and the lapped Alu HSF first and recheck temps. Then I'll try it without the slug and we will all know for sure.
Click to expand...

Go for it, we may learn something.
 
K, got the Alu HSF lapped and removed the existing lightly lapped copper slug and Vmodded the GPU to 1.48v and the new idle temp is 56*C. I know I should have Vmodded the card after getting a new temp but I was impatient. I'll remove the Vmod before I go to putting the highly lapped copper slug in there and rechecking it, then I'll get a Vmodded temp for that config as well.
 
This table is a sample that shows you the thermal conductivity of different material.
http://hyperphysics.phy-astr.g...base/tables/thrcn.html

Looking at the column on the right, the unit is Watts per meter in degrees Kelvin.

You can see that Diamond is a great thermal conductor. Its thermal conductivity is 1000W/m.
Copper is 385 and Aluminum is 205.
You can also see that air is a poor thermal conductor with a value of 0.024.



This article compares the thermal conductivity of different thermal pastes to metal.
http://www.overclockers.com/articles662/
You can see that Arctic Silver 3 is only 9W/m.


Summary:
Copper -> 385
Aluminum -> 205
Arctic Silver 3 -> 9
Air -> 0.024

Thermal paste is 400 times better than air.
That is why you should never run without paste!

But, it is 20 times worse than Aluminum.

By inserting a slug, you are adding one layer of thermal paste that did not exist before. Even if the slug is from Diamond, you will still be degrading the overall thermal conductivity.
 
With lapped Alu HSF, 1/8" highly lapped copper slug anf 1.48v GPU Vmod still in place idle now teeters on 54/55 *C 😀

OWNED !!!!

Thanks for your input all that said it would do no good at all even if it was only a minor decrease but you LOSE !!!! And yes I'ma gloat because you only assumed, I'm pretty sure you have never tried it before or maybe you wouldn't have chimed your oppinion in as fact 🙂

I win, you lose. Thank you , come again.
 
Originally posted by: Dazed and Confused
With lapped Alu HSF, 1/8" highly lapped copper slug anf 1.48v GPU Vmod still in place idle now teeters on 54/55 *C 😀

OWNED !!!!

Thanks for your input all that said it would do no good at all even if it was only a minor decrease but you LOSE !!!! And yes I'ma gloat because you only assumed, I'm pretty sure you have never tried it before or maybe you wouldn't have chimed your oppinion in as fact 🙂

I win, you lose. Thank you , come again.
Click to expand...

Ambients and all test conditions the same for both tests? If they are then nice going. However, I'd say 1-2C is within the possibility of error.
 
Not error, every time I rebooted I get the same idle and theres the fact that I can bench 05 @ 585/1290 now and before the slug I couldn't bench @ 570/1280 when before all this my best was 555/1280 🙂

Oh, I'm now 23rd overall for anyone running single or Sli 6600GT's 🙂 on 3DMark05, last night I was 28th 😀
 
Originally posted by: Navid
This table is a sample that shows you the thermal conductivity of different material.
http://hyperphysics.phy-astr.g...base/tables/thrcn.html

Looking at the column on the right, the unit is Watts per meter in degrees Kelvin.

You can see that Diamond is a great thermal conductor. Its thermal conductivity is 1000W/m.
Copper is 385 and Aluminum is 205.
You can also see that air is a poor thermal conductor with a value of 0.024.



This article compares the thermal conductivity of different thermal pastes to metal.
http://www.overclockers.com/articles662/
You can see that Arctic Silver 3 is only 9W/m.


Summary:
Copper -> 385
Aluminum -> 205
Arctic Silver 3 -> 9
Air -> 0.024

Thermal paste is 400 times better than air.
That is why you should never run without paste!

But, it is 20 times worse than Aluminum.

By inserting a slug, you are adding one layer of thermal paste that did not exist before. Even if the slug is from Diamond, you will still be degrading the overall thermal conductivity.
Click to expand...

Use the same math for water. And it should become very clear why water is so powerful.


Lastly, op, im sorry for the first post. But i was just suggesting an alternative.

The copper slug wont work because the top base needs to absorb and disapate the heat quickly. Your trying to confuse a TEC concept here.

TEC blocks require a Copper base plate to transfer heat more efficiently then the ceramic itself. The reason is because the copper plate is more flat, and there are less chances of a bubble on a copper plate vs a Ceramic TEC plate.

Now you cant compare a alu cooling base with a TEC plate. One disapates energy though convection, while the other uses energy to MOVE it.

And also when you add the plate, you will increase its resistance to absorb the heat and radiate it. This is why it wont work. And believe me, if people could make the TEC plate extremely FLAT like a copper plate, the copper would be removed entirely.


So i still stand by my recomendation. A cheap aftermarket airsink will give you much better results then adding a copper plate in the middle.
 
God I love it when people just refuse to give up on a cause when they've clearly lost ROFL.

Temp with just the lapped HSF 56* C @ idle and couldn't even complete a run of 3DMark05 @ 570/1280

Temp with lapped copper slug between Alu HSF and GPU teeters on 54/55* C @ idle and I was able to complete a run of 3DMark05 @ 585/1290 for a score of 4350 that put me 23rd overall for 6600GT score on any platform 🙂
 
*sigh*

His tests proved physics wrong. I wouldnt hold it valid. But i was going to PM him these today. I was a bit rude to him last night. I had issues with my other rig so i kinda let it out on him.

BUT.

http://www.procooling.com/inde...=articles&disp=71&pg=1

"Myth #2. Copper absorbs heat better than aluminum, but aluminum "gives up" heat better than copper.


"The Z4 Aqua is the direct result of 3 yrs worth of ongoing R&D by CPU-FX .The Z4 Aqua has had several different maze designs prior to their new Gear Star maze design and while I really cant comment on how the older designs performed ,the new Gear Star maze design performs admirably. The newly designed Z4 Aqua combines a gear-star mazed silver plated copper alloy core for maximum heat absorption with an aluminium top for maximum heat dissipation"

-AMDMB
http://www.amdmb.com/article-display.php?ArticleID=189


I am not sure where exactly that thermal conductivity was first split into two aspects, "taking in" and "giving up", but AMDMB are by no means alone in making this type of statement. Interestingly, Myv65 of AMDMB addresses this myth directly in their "General Heat Transfer Guide". To briefly summarize Dave's thoughts, the only real advantage that aluminum has over copper is its density. If one is trying to remain within AMD or Intel's weight specifications then it is possible to produce an aluminum heatsink that is larger and with greater surface area. However, if two heatsinks are of identical size and construction then the copper unit will perform better. The real reason aluminum heatsinks are common is the low cost and ease of producing them. Copper isn't the ideal material to work with, as any machinist can tell you."


Your test and results just butchered one of our great thermodynamics RULE in physics. So no your test is off.
 
Yup. Idle still at 55* C and I can still bench @ 590/1290 vs not even being able to complete a run of 05 without GPU lockup @ 570/1280 without the copper slug.

Dunno how to explain results : / Guess they kinda explain themselves.

My OP asked if anyone thought it would help. I tried the Alu HSF alone after I lapped it and the results weren't as good as "after" I aded the 1/8" copper slug.
 
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