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Project: Geforce FX 5900(XT) heatsink cover for modern fans

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First post, by Gabriel-LG

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A few weeks ago, I got lucky and found this (sad looking) Geforce FX 5900 XT, mislabeled as Radeon 9600SE (untested). So I put in a generous offer for a 9600SE and sealed the deal.
With the fan that was glued in, the card was overheating (no kidding), but down-clocked to 100 MHz, it worked perfectly stable 😁

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Since I could not find a suitable replacement fan anywhere, I bought the closest match I could find. A 45mm frameless fan with 39mm triangular mounting holes. The only issue is that modern fans are too thick (10 mm instead of 5 or 6 mm).

To make this card look and perform like a FX 5900 XT again, I designed and 3D printed this custom shroud to guide the airflow.

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If you want to use my design for your own FX-5900(XT), be my guest! Please post a reply with photo in this thread.

The fan I bought is very powerful but too loud (I know 5900 cards are supposed to be loud, I have no reference). Anyway, cools great since I cannot push the card over 55 °C in a 30 °C room. I will go look for a less powerful fan, or for a way to turn this fan down a notch (without ruining the looks; I hate GPU fans connected off-card).

Last edited by Gabriel-LG on 2026-07-27, 20:23. Edited 5 times in total.

Reply 1 of 4, by Gabriel-LG

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I am hereby publishing my design under the CC BY-NC 4.0 license.

  • This cover is designed for the reference cooler of the 5900/5900XT PCB with L-shaped memory arrangement (P177)
  • It should also fit on the PCX-5900, some FX-5200/5600-Ultra models and the Quadro FX-1000/1100/1300 cards
  • My current prototype is printed in PLA+, but for durability I would recommend using PETG instead.
  • To preserve the look of your card, you should be able to stick the original cover plate onto this cover, using 3M 300LSE tape (use a smooth print-bed in that case)
  • If you have any suggestions for improvements, please post a reply!

Reply 2 of 4, by TELVM

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Awesome job, congrats! 👍

Gabriel-LG wrote on 2026-07-27, 19:56:

... a way to turn this fan down a notch (without ruining the looks; I hate GPU fans connected off-card).

Insert a resistor on the +12V (red) wire of the fan. This will lower the voltage it receives, and thus the rpm.

One 51 Ω resistor will drop voltage to ~8.5 V
One 81 Ω resistor will drop voltage to ~7.3 V

That's what Noctua "Low Noise Adapters" are, just resistors to lower the fan's voltage.

file.php?mode=view&id=246411

Let the air flow!

Reply 3 of 4, by zapbuzz

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this is a great story.
Although you say the fan is too loud and stuff it would extend the life of the GPU if you could tolerate it
Those cards are getting hard to find because gaming enthusiasts shy away from bus powered "passive" cards as they don't perform for overclocking well and tend to destabilise.
Your card is an overclockers choice with its molex to PSU connector though personally I’ve never used overclocks that I was happy with the stability at stock.

Reply 4 of 4, by Gabriel-LG

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TELVM wrote on 2026-07-27, 21:01:

Awesome job, congrats! 👍

Insert a resistor on the +12V (red) wire of the fan. This will lower the voltage it receives, and thus the rpm.

Thanks 😀 I considered that. The fan just does not have that much wire to work with. The wires are 30 AWG, that is 0.05mm2. soldering a resistor inline will look very bulky and will be fragile.

zapbuzz wrote on 2026-07-27, 21:27:

this is a great story.
Although you say the fan is too loud and stuff it would extend the life of the GPU if you could tolerate it

Thanks 😀 It is only just bearable, to the point that I feel relief when the system powers down 😦

My estimation/math was off somewhere so I picked the most powerful fan I could get my hands on.
In my mind, a 10mm fan with 11 blades spinning at 3300 rpm, should move significantly less air than the original 6mm fan with 13 blades spinning at 5000 rpm.
Luckily less powerful fans are easy to find!

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