Thread: Heatsink Mod?
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Old January 14, 2013, 07:13 AM
Masteroderus Masteroderus is offline
Join Date: Oct 2011
Location: Edmonton
Posts: 642

My System Specs


The guy is saying 5 degrees cooler at load when he taped up the sides of the heatsink.

I'm sorry to be so critical, but he didn't post his ambient temperatures, so the data is useless. The real number to look for is change in temperature (load temp - ambient temp of room).

So let's put our physics thinking caps on and try and figure out what is going on inside the heatsink.

The CPU generates heat and transfers it to its integrated heat spreader, which transfers heat to the thermal interface material, which transfers it the heat pipes and the metal base plate in which the pipes are embedded.

The heat pipes transfer heat to the body structure, which is finned to maximize surface area. Heat does rise, and the heatsink will work, somewhat, without the fans plugged in, because as the hot air rises it makes a pressure differential near the surface of the heatsink that sucks "fresh" air in ("in" being to the surface of the heatsink).

Covering the side fins does focus the flow of the air more, but it also removes the ability for the air to travel orthagonally (at 90 degrees to the fan) through the heatsink.

Think about the mass of air going through the heatsink. It would equal the flow rate (m^3/sec) times the density of air (kg/m^3) = kg/sec. This same mass of air would go through the heatsink regardless of the side shrouds (approximately). But one path has more surface area of heatsink, the path that includes the sides open.

This is why coolermaster, a very reputable and old cooling company, did not include 2 cents worth of duct tape, or a 2 cent molded plastic shroud with the 212. 5 degrees is A LOT for a 2 cent mod, and I am fairly sure that if the side shroud mod worked it would be included with the 212. If the 212 was 5 degrees cooler at load it would mean BIG business for coolermaster because it would basically kill off a lot of competition.

Now, if you were paying close attention you can see from my analysis what you can do to increase the efficiency of your heat sink. If the mass flow of air through your heatsink is the product of density and volumetric flow rate, you have a free parameter to play with without modding the 212; density.

PV=nRT => V/n = PRT => V/n ~ P

You can increase pressure inside your case which will, both theoretically and from first hand experience, increase the efficiency of your air cooler. Just add more intake fans while keeping the cpu exhaust fan an exhaust fan.

Anyways, I hope this helps, and I'm not making this stuff up, it's basic thermodynamics which I have formally studied.
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