Which is better for dissipating?

Which heat sink dissipateds heat better... Copper or Aluminum?

copper


oops, forgot I was in the memory section and not cooling . For memory cooling kits, you have to make sure that each memory chip is in contact with the heat spreader. I just have a fan blowing over the ram.

copper is the best heat dissapation meterial, thats why houses are wired with copper (im an electrician) hehe
-Andy

Ah, not true. Copper conducts heat better, aluminum dissipates it better (in this case I'm taking better to mean "faster"). It has to do with the specific heat properties of each metal. This is why you see aluminum heatsinks with copper slug cores.

This should be in the cooling section, where lots of people will argue about it.

Copper is king. Aluminum is second best to it.

Copper is a good heat conductor but for Memory you don't want it absorbed and held next to the chip you want it to help dissipate the heat. For Memory you want to use Aluminum because it works better than with normal convection.

Ah, not true. Copper conducts heat better, aluminum dissipates it better

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If something conducts heat better, it also dissipates it. Correct? I think the 'aluminum dissipates better' is a common misconception. Look at the SLK's - they're the best heatsinks out there, and they're solid copper. The reason heatsinks have copper slugs and aluminum fins is because the copper conducts heat to the aluminum fins better than aluminum, and from there out aluminum is cheaper, ligher, easier to work with, and gets the job done.

johan851 said:

If something conducts heat better, it also dissipates it. Correct?

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Nope. Conduction is when heat moves through a material, dissipation (or more correctly, convection) is when heat moves from one material to another (i.e. from a heatsink to air).

Copper can conduct air much better. Although copper has a specific heat slightly lower than aluminum, if you have a fan blowing over the ram (or even good airflow in the case) the copper will perform much better than aluminum. Cant argue that keefe...copper will outperform aluminum 99/100 times in cooling.

JKeefe said:

Ah, not true. Copper conducts heat better, aluminum dissipates it better (in this case I'm taking better to mean "faster"). It has to do with the specific heat properties of each metal. This is why you see aluminum heatsinks with copper slug cores.

This should be in the cooling section, where lots of people will argue about it.

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correcto.

Copper is the better conductor, alu is the better disipator.

johan851 said:

If something conducts heat better, it also dissipates it. Correct? I think the 'aluminum dissipates better' is a common misconception. Look at the SLK's - they're the best heatsinks out there, and they're solid copper. The reason heatsinks have copper slugs and aluminum fins is because the copper conducts heat to the aluminum fins better than aluminum, and from there out aluminum is cheaper, ligher, easier to work with, and gets the job done.

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nope. Take a look at the Alu/copper Thermalright alx-800. Virtually identical to its all copper brother in dimentions, the slk-800, yet it performs virtually identically, and in some cases better.

Just because the top performers are all copper doesnt mean all-copper is the best material to use. Everybody knows granite would own - but they dont use that.....(yes i know that sbecuase of the price......)

Anyway, it's a fact that alu/copper hybrid's are better performers than all-copper sinks. If thermalright have their heads screwed on - they'll be releasing hybrids of their 'SP' range. Lighter, cheaper AND better.

Here's hoping.

james.miller said:

Just because the top performers are all copper doesnt mean all-copper is the best material to use. Everybody knows granite would own - but they dont use that.....(yes i know that sbecuase of the price......)

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Haha. I think you mean graphite (i.e. diamond). Granite is a rather unremarkable igneous rock.

It seems that we are split down the middle here. Here is a thought for all of you. If you have a bowl of hot soup and you place two spoons in it, one copper and one aluminum, which will get hot the quickest? Most of us use aluminum spoons. I think becouse of cost and the fact that aluminum does not conduct heat. I have never eatten with copper so I do not know. But this would seem logical. Please let me know your continuing thoughts on this subject.

JKeefe said:

Haha. I think you mean graphite (i.e. diamond). Granite is a rather unremarkable igneous rock.

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bah.

lol

Aluminum does not dissipate heat much better than copper and that difference gets even smaller with air blowing over both materials. However, copper is almost twice as conductive which easily outweighs aluminums slight advantage in heat dissipation. I think if a Al/Cu hybrid was the miracle combo you speak of james, Thermalright would have that on their flagship SP line...

james.miller said:

nope. Take a look at the Alu/copper Thermalright alx-800. Virtually identical to its all copper brother in dimentions, the slk-800, yet it performs virtually identically, and in some cases better.

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no mention of the word 'miracle' in my posts, NO LIFE. if you care to do a little digging, you'll see that 9/10 test show the alx and slk 800's to be neck and neck. yet the alx is, once again, lighter and CHEAPER. Thats what they really have going for them.


As for not being so good - one of thermalrights best heatsinks for the time was the ax-7. you guessed it - it was an alu/copper hybrid. the alx-800 is released....and for the money it is again one of the best you can get.

What would happen if/when they do the same for the sp range?

edit: one such review
http://hi-techreviews.com/modules.php?name=News&file=article&sid=38

Enough arguing, the heatsink reviews rarely use the same fan on all their comparison tests.

Look at the SLK's - they're the best heatsinks out there, and they're solid copper.

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I did a back-to-back test of an all copper and highly touted SLK900 versus an Alpha8045, which uses a copper insert/forged Alu fin construction. I used the exact same fan, which was an 5800 rpm 80 mm Vantec Tornado. I tested this on an AMD setup with an XP1700+ running 2400+ mhz, a real oven. The Alpha beat the SKU by 4-5 C!!! It ran around 47C while the SLK ran 52 C. One problem I see with the SLK is that the fins should be angled to the airflow to scrub off heat (a la automotive radiators). Otherwise the air just blows right by the thin fins. To me, it seems copper holds heat too long.

I posted this on the cooling section of this forum and boy, did the SKU fanboys come crawling out of the woodwork. All the pro reviews show the Alpha far behind, but this sink came out a long time ago and all the reviews tested with a low rpm fan, not the same fans used on the later SKU reviews.

I still own the SKU and it's sitting on the shelf collecting dust. I got no bones to pick and you can guess what sink I use on my AMD rigs for air.

Now Intel can bloody well choose any heatsink design they want for their CPUS, but did ya notice the latest OEM sinks on their 3.0-3.2Cs use - guess what - a copper slug touching the CPU with aluminum fins. Cost saving you say? I'd think an all-copper sink is less costly to manufacture than copper inserts press-fitted to aluminum fins.

whaaat when your talking mass production a press is the least of there costs... thats not true. im telling you in my electrical classes we looked at all the properties of metals and as a stand alone metal copper stays the coolest.

now im not saying that these aluminum heatsinks arent capable but maybe its the airflow/design that makes it compete the metal itself can not compete. if you had 2 identical heatsinks with identical fans, the copper would outperform the aluminum.

now you look at the properties of aluminum it heats up really fast, but if you can get that heat off it fast you can remain cool.

now copper takes a little more to heat it up, and i think this is the reason for the combo, if you think about it the copper sits right on the CPU which can take the initial heat for a longer period before it reaches a certain temperature, now the aluminum which heats up quicker also cools down quicker so you cool the copper center with the aluminum.

i dont know how legit this is but its only thing i could think of besides cost to put aluminum on the outside.
-Andy

no mention of the word 'miracle' in my posts, NO LIFE

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No...I am calling it that My point is. If the al/cu combo is so great, then why didnt thermalright use it on their top of the line cooler? Doesnt make sense that they would choose a heavier and more expensive material that supposedly doesnt perform any bettter.

If the al/cu combo is so great, then why didnt thermalright use it on their top of the line cooler?

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Very simple reason for that: they stick with their basic design. I dunno whether they have a patent for it. That design may not work well with the Cu/Alu hybrid (really thin fins, thick base).

Off hand, I would say that thin Alu fins of that design will not draw heat away from the base effectively with a thick copper base like that. You need all copper to conduct the heat. The fins could be made thicker of Alu, but then they are fan-shaped and may not dissipate heat as effectively as separate round fins, e.g. the Alpha, which are in fact 5-6 sided, perhaps for maximum heat dissipation. IMO, you don't want the copper base too thick, just enough to transfer the heat to the Alu fins.

Then when it's all said and done, how does the design perform compared to other designs? My testing is an example here. Again, using the exact same fan for cooling.

yeah it would definatly be an interesting test. if you think about it also the aluminum fins are thicker which makes less room for air to travel through and less fins total to cool....

just another thought.