Small desk fan as CPU fan

goedelite

Reputable
Feb 16, 2014
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What ham is there in cooling the CPU by removing the CPU fan and using a small external fan, such as a small personal desk fan to blow air directly onto the heat sink from the case vent that is directly in front of the CPU? Rather than trouble to replace an original CPU fan, I am thinking of just removing it and using the above arrangement, maybe with a dust screen over the case vent. It will take a bit of space and make more of a whir, but I cannot foresee any other problem. Am I neglecting something?
 
Solution
Well when coolers dont operate quietly people get upset (IE AMD stock coolers).
That being said, if you wanted to use the fan in addition to the CPU heatsink it should improve temps a bit. That is only to get more cool air to the processor, and the hot air away.
The fin density on the heatsink itself requires the fan with higher pressure, but possibly less airflow. If you mix both you have a better cooler.
I doubt it would work properly. CPU fans on the CPU heatsink spin at much higher speeds with higher static pressure than a desk fan. I doubt the desk fan would be able to provide enough airflow to the heatsink to even prevent overheating, let alone make things better.
Replacing a CPU cooler takes ~10 minutes if that, if all you needed was a desk fan they wouldnt be using heatsink fan combos.
 
I am not sure I want to risk damaging my CPU, but I am skeptical of your analysis for the following reason. (If my reasoning is faulty, I am ready to be corrected.)
What is important is air flow not air pressure. The air flow from the CPU's fan as observed where the warm air emerges from the case is very low. Placing a small desk fan where it can add to the CPU fan's output increases it significantly. It can be felt to increase noticeably at the exits from the case. I would estimate that it more than doubles the outflow from the case. The case itself feels cooler on the motherboard's side with the assisting desk fan. The CPU fan by itself produces only a very gentle output that just causes a strip of bathroom tissue to flutter at the case-exit. For that reason, I thought my CPU would operate at a lower temperature with a desk fan than with the designed CPU fan. The CPU operates at about 37°C, according to "Speccy" with only the CPU's fan. It may have been designed for minimal noise rather than for optimal cooling. Marketing dominates engineering. Notice the advertising for CPU fans and case fans: "Whisper speed control" and other such nonsense.
 
4 choices

1. Just do it and see what happens

2. Take our advice and don't do it because it's silly, pointless, and probably won't work that well

3. Take the time to do the calculations on air flow over the heat sink, then do the heat transfer calculations based on the available thermal output data available on the net for your CPU the effectiveness of the heat sink, etc and prove us wrong.

4. Say screw it and throw the entire thing into a cooled aquarium tank filled with oil because at this point you're doing it for the lolz
 
Well when coolers dont operate quietly people get upset (IE AMD stock coolers).
That being said, if you wanted to use the fan in addition to the CPU heatsink it should improve temps a bit. That is only to get more cool air to the processor, and the hot air away.
The fin density on the heatsink itself requires the fan with higher pressure, but possibly less airflow. If you mix both you have a better cooler.
 
Solution