I was just curious how much of a difference having the fins makes in a heatsink vs just a large block of metal.

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    While the short and simple versions provided below are correct, this is a big enough subject in general for mechanical engineers to spend two semesters on... Jul 15, 2010 at 19:16

3 Answers 3


The heat radiates from the surface of a heat sink, so the greater the surface area, the better the heatsink. Roughly speaking, if you cut a load of slots in your big block of aluminium, you could end up with, say, 5 times the surface area, and the heatsink can then get rid of 5 times the heat.

Have a read of the Wikipedia article - the big block is, in general, rather poor compared to the fins.

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    Oh for a giant copper serpinski sponge...
    – Everett
    Jul 25, 2012 at 20:27

Fins give you more surface area for cooling, a large block has less surface area and would still have a hotter center than something that can get air right to the center of "the block".


The difference between a special heatsinks and an aluminum (metal) block is very big, I can easily tell the following three differences:

  1. The heatsinks will have a significantly larger surface area than the aluminum block through a different structure, so that it has a more efficient heat dissipation function.

  2. The weight of the aluminum block of the same volume is much heavier, which is not suitable for many applications.

  3. Due to its weight, the price of aluminum blocks far exceeds that of special radiators. For example, the most widely used extruded heatsinks are made easily by professional manufacturers and they are basically priced according to the weight of the parts. This heatsink manufacturer has some detailed information about the extruded aluminum heatsinks.

In summary,the above comparison makes the aluminum block's cost-effective heat dissipation completely no advantage.

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