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92mm CPU Fan Replacement Project

By on June 25, 2022
92mm CPU Fan Replacement Project

The issue

To save on cooling costs at home I don’t run air conditioning during the Summer so need to be sure my computers are hardened to the heat; for this, as well as recapping the power supplies I also attend to the fans used for cooling. The problem, however, was that the CPU fan on my main computer at home is of strange standard, a round 92mm fan with the mounting holes of a square 80mm fan (71½ mm hole spacing).

design fan

The solution

Since there is a better selection with the more standard 92mm square fan (82½ mm hole spacing), I thought to make a conversion plate as I wanted to try a Noctua NF-A9 fan as a replacement, partly due to its claimed 150,000-hour lifetime and partly due to Noctua’s reputation for quiet running, although I was concerned that it might not have sufficient flowrate for the CPU’s cooling needs.

While there is a black version of this Noctua fan, which is more expensive, I went with the standard Noctua colors which take a little getting used to.

noctua square fan

The Noctua redux series is cheaper and better looking while still having the 150,000-hour lifetime

Noctua Redux version

but does not have such a good flow rate or pressure head rating as the new offerings, and since I was already replacing the original fan with one that was less powerful, I did not wish to take the risk.

The design

In the conversion plate design (I went through several versions) I was careful to avoid thin sections that would have weakened the plate.

conversion plate design

Now while it might have been easiest to just cut this plate out of some material by hand, I thought it would be educational to 3D print it, and in preparation for this I used the free edition of the Autodesk Fusion 360 CAD program which, while it had restricted functionality, was sufficient for the task although I would have liked the spline fit feature of the full version. One nice ability of the program is that it can generate a rendition of how the result may look.

Fusion 360 rendition

Along with this it can also output an Engineering drawing to scale

Engineering drawing

The production

A local 3D printing club helped me print the resulting STL file as I don’t have a 3D printer of my own; since the club was doing me a favor, I didn’t get to choose the color or material (PLA), but still felt the actual result came out rather well and only used about 15¢ of material.

3D print

This progress motivated me to finally order the Noctua NF-A9 fan and I included a protective fan grill as one was present on the original round fan.

Assembled project

The testing

Fortunately, the original design didn’t need any further alterations as the project worked well on the first try; CPU temperatures under load remained reasonable even though the original fan was 7W and the replacement just 1.2W

Another virtue of the Autodesk Fusion 360 CAD software is that it can also be used for circuit board design which may be useful in a future project.

andy sheikh anwar

This article was written by Anwar (Andy) Shiekh originally from London, England; he repairs things to help make an income go further and presently teaches Physics in Colorado, U.S.A.

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Note: You can check his previous repair article on AUKEY (CB-H5) USB 3.0 Hub Repair



  1. Albert van Bemmelen

    June 25, 2022 at 11:31 pm

    Good job! I am still curious for what computer/mainboard your Fan design was intended since you didn't mention any of it? Also because it may also be usefull for my own quad-core computers, including the .stl design that you could share? I have a Creality Ender 5 pro printer myself and my brother uses Sketchup to design objects to replace broken parts at home which I 3D print for him and for myself. And I am planning to add a very much needed filament run-out detection that pauses an 3D print within 0.7 seconds when the filament breaks or stops. Including a bedlevel touch sensor to automate the bedleveling which I believe only the larger Ender 5 Plus standard already uses.

    • Anwar Shiekh

      June 26, 2022 at 10:34 pm

      A quad core HP/Compaq 8000; I would be happy to share the file if I knew where to send it.

    • Anwar Shiekh

      June 29, 2022 at 2:16 am

      If I had an email, I'd send you the file.

  2. Lawrence Mc Coig

    June 26, 2022 at 2:02 am

    I hope to visit Colorado shortly. I hear the humidity is low usually. So, why not run an air conditioner as compressor would not run continuously and have fan only at times?

    • Anwar Shiekh

      June 26, 2022 at 10:32 pm

      It is indeed very dry out here and people use swamp coolers, but I don't like the resulting humidity. But I do run a lot of fans in the house and ones on variacs in the bedrooms to cut noise.

  3. Imoudu.O

    June 26, 2022 at 3:52 am

    That's an intelligent conversion,thanks for sharing.

  4. Parasuraman S

    June 26, 2022 at 10:20 am

    Vow! That was an out of the box thinking and fabrication done! Excellent motivation for technicians like me! Many thanks for sharing this wonderful article!

  5. Lynn Blakely

    June 28, 2022 at 4:17 am

    That was an informative article Anwar (Andy) Shiekh It is nice to have friends that like to help others with a project, such as the one that you needed. That new fan is more energy efficient, as a plus.

  6. Lee

    June 28, 2022 at 7:50 am

    I use wetransfer for large file transfers.
    You could upload your file and share the address here as a reply to Albert.

    • Anwar Shiekh

      June 29, 2022 at 1:59 am needs an email to send the file to; I don't have an email for him

  7. Waleed Rishmawi

    June 28, 2022 at 2:29 pm

    wow that is great lucky to have a 3 D printer because I do not have it so far but planning on it any time soon. thanks for sharing and have a blessed day

  8. Justice Cele

    June 29, 2022 at 8:29 pm

    Thank you (Ngiyabonga) Andy. truly a physics educator, wow.

  9. Yogesh Panchal

    July 4, 2022 at 12:28 am

    kde1209ptvx original FAN rpm rated 8000RPM & Noctua NF-A9 rated 2000RPM Only.
    CPU FAN Must be as per the technical specification provided by the manufacturer of the CPU else CPU performance will gradually decrease and may be spoil the CPU because of overheat.

    • Anwar Shiekh

      July 4, 2022 at 11:30 pm

      A most valid point and it was my main concern.


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