this post was submitted on 03 Mar 2026
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[–] fx242@lemmy.world 6 points 1 week ago* (last edited 1 week ago) (3 children)

Why copper? Aluminum work way better as a dissipation surface.

[–] SomeoneSomewhere@lemmy.nz 18 points 1 week ago (1 children)

Copper has more mass, heat capacity, and thermal conductivity per litre.

Is aluminium actually more effective as a dissipation surface? I hadn't heard that.

[–] fx242@lemmy.world 6 points 1 week ago (3 children)

Copper is better conductor but it's worse at dissipation. Do the experience yourself, heat a block of each and then touch them afterwards.

[–] ulterno@programming.dev 1 points 6 days ago

The problems and complications with your method:

  1. Suppose Cu is much faster at heat transfer and you only briefly touched it. Your skin does not actually sense temperature, but rate of heat transfer, which depends not only upon the material temperature but also upon how well it will transfer heat. Better use a thermometer.
  2. As explained in https://lemmy.nz/comment/20463232, you need to make sure both have been given the same amount of thermal energy and not just heated upto the same temperature. The best way to do so, is by embedding a heat generator right in the middle of the block and transferring a measured amount of energy. e.g. You can embed an electric heater wire (you will require insulation too. That's your headache (ceramic, perhaps)) and pass current using a power source that gives a measurement of the total energy.
[–] SomeoneSomewhere@lemmy.nz 8 points 1 week ago (1 children)

Is that not because the copper holds more heat, so stays hot for longer at the same dissipation?

[–] fx242@lemmy.world 4 points 1 week ago (2 children)

Maybe you're right, but I remember than in the 2000s I've had identical cpu heatsinks in both copper/aluminum versions, and the aluminum one had better performance. And then they started to make hybrid ones, stating that the copper part was to allow rapid heat transference, and the aluminum part to improve dissipation. But maybe its all marketing.

[–] Schmuppes@lemmy.today 6 points 1 week ago* (last edited 6 days ago) (1 children)

Aluminium is significantly cheaper, that's why they make coolers with a copper base and alu fins. It's a good compromise.

[–] ulterno@programming.dev 1 points 6 days ago

I just thought of another reason for using Al this way.
Since the heat is being transferred to air, which would be much slower than the 2, using larger fins with lesser thermal conductivity might be more desirable than smaller fins with higher conductivity.
This would also be accompanied with other design changes like greater fin-fin gap, which is better for use with lower pressure fans.
So overall cheaper design and lesser noise.

[–] SomeoneSomewhere@lemmy.nz 3 points 1 week ago

Aluminium is cheaper and lighter.

This seems to suggest that the metal-air transmission is virtually identical between the two, and cites some sources: https://electronics.stackexchange.com/questions/255731/copper-or-aluminum-heatsink

[–] MoffKalast@lemmy.world 3 points 1 week ago* (last edited 1 week ago)

Dissipation = thermal conductivity. Copper is better in both, it's just heavier and far more expensive. Are you sure you put the same amount of energy into both blocks there? A copper heatsink can generally be much smaller than an aluminium one.

[–] Gaja0@lemmy.zip 12 points 1 week ago

Technically, copper is better at heat dissipation. Aluminum is prefered because it's cheaper and lighter. For an aluminum heat sink, you could have an smaller equally performing copper heat sink. In fact, this is the case for when weight and cost isn't a priority. Some heatsinks even use a copper core to wick away heat to the rest of the aluminum heat sink.

[–] zod000@lemmy.dbzer0.com 2 points 1 week ago

From what I have always understood, copper is technically better, but it isn't dramatically better and it is heavier and more expensive. You likely couldn't make a heatsink like the full sized Noctua's and just mount them the way we do because of the weight alone. The price would also likely be double to triple.