CFM in air-cooling

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greens
Nope!
It is much more complex than that. Your PC could be in a wind tunnel, but that doesn't help anything if your CPU cooler is crappy.

Even if you have the best CPU cooler money can buy, you still have to deal with the ability for the cooler to conduct, and then radiate.

The Copper heat pipes must take heat from the CPU, and they do so at a fixed rate. Then the heat must be radiated off of the pipe, into the aluminum, which also radiates. All of this happens at a fixed, known rate.

Increasing airflow beyond the ability for the metal cooler to dissipate it is pointless.

Airflow should be as low as possible without seeing an increase in temps, anything beyond that is a useless waste of power and noise.
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greens

greens

Splendid
Jan 27, 2012
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Nope!
It is much more complex than that. Your PC could be in a wind tunnel, but that doesn't help anything if your CPU cooler is crappy.

Even if you have the best CPU cooler money can buy, you still have to deal with the ability for the cooler to conduct, and then radiate.

The Copper heat pipes must take heat from the CPU, and they do so at a fixed rate. Then the heat must be radiated off of the pipe, into the aluminum, which also radiates. All of this happens at a fixed, known rate.

Increasing airflow beyond the ability for the metal cooler to dissipate it is pointless.

Airflow should be as low as possible without seeing an increase in temps, anything beyond that is a useless waste of power and noise.
 
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Solution
JackNaylorPE

JackNaylorPE

Titan
BANNED
Oct 30, 2004
32,255
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99,960


The correct answer is yes and no.

1. There is little correlation between advertised fan specs and performance because, to use a word in common usage these days, advertising presents "alternative facts". See article below

https://martinsliquidlab.wordpress.com/2013/02/18/why-static-pressure-max-flow-specs-are-poor-measures-of-fan-performance/

2. Any such correlation can must start with one basic premise "all other things being equal". In other words, any data you gain is relative to performance on ant specific cooler and any single build. Of course, as with any experiment, this is an absolute necessity so I will assume going forward that this was the premise of your question

3. Increasing fan speed improves performance. It is not linear, tho nearly so and a simple equation will not suffice, it also depends whether flow is laminar or turbulent, the shape, spacing, material of the heat sink.

You can see how in the bar charts here (ST30 360mm rad used):

https://martinsliquidlab.wordpress.com/2012/05/01/alphacool-nexxxos-st30-360-radiator/4/

600 rpm = 96 watts (0.160 watts per rpm)
1000 rpm = 150 watts (0.150 watts per rpm)
1400 rpm = 199 watts (0.142 watts per rpm)
1800 rpm = 242 watts (0.134 watts per rpm)
2200 rpm = 281watts (0.127 watts per rpm)

You will also note that while the 30mm thick radiator excelled at the lower speeds, thicker rads took over the lead when more oomph (rpm) was provided.

4. While there are design differences in fans will improve cooling efficiency, these are secondary to fan rpm. Switching fans to reduce noise will generally come with a substantial reduction in cooling efficiency



 
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gdmaclew

gdmaclew

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May 20, 2008
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The heat is not "radiated" from the copper heat pipes to the aluminum...that is conduction. You are correct that the aluminum radiates to the surrounding air. The "steady state" is reached when no more heat can be transferred at that delta T. Lower the temperature of the surrounding air (in the wind tunnel for instance) and a new lower steady state will be reached.
Air is not as efficient as a liquid because though both are fluids, air is less dense than liquids and has a lower capacity to transfer heat.
 
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