Ever wondered how Nvidia’s GeForce RTX 4090 or GeForce RTX 4080 Founders Edition axial fans work outside of the graphics card? chifel forum (opens in new tab) (via Orlac (opens in new tab)) has the answer. He repurposed axial fans from his two best graphics cards for top-down CPU coolers and shared the results.
The axial cooling fan seemed to keep the forum member’s Core i5-13600KF’s operating temperature 9 degrees Celsius and 5 degrees Celsius lower than the Thermalright TL-C12 and Cooler Master Mobius 120P ARGB respectively during the Cinebench R23 benchmark. The noise level during normal operation was also reported to be lower than other fans. However, the axial fan makes a humming noise at very low RPMs, making it more audible than the other his 120mm and his 90mm he tested.
Nvidia utilizes a combination of Nidec’s AD4A31K04 and AD4A31K05 cooling fans for its GeForce RTX 40 series (Ada Lovelace) Founders Edition graphics cards. His Nidec Servo, a subsidiary of the Japanese manufacturer, shot to great fame in 2009 with the development of his famous Gentle Typhoon fan. With such an impressive pedigree, it’s easy to understand why Nvidia chose Nidec to provide the active cooling solution for its Founders Edition products.
The AD4A31K04 and AD4A31K05 are similar in core, but differ in airflow direction. Recall that Nvidia uses a dual-axis fan design to push air in different directions. The seller labels the fans Type A and Type B. The former pushes air forward of the blades, while the latter directs air downwards into the motor.
Fans are usually $20 (opens in new tab) On Chinese online platforms such as AliExpress and Taobao. However, the latter merchant sells fans at a lower price. $1.50 (opens in new tab) — I’m not kidding you. The ridiculously low prices allow DIY enthusiasts to try the He AD4A31K04 and Her AD4A31K05 beyond the product’s natural range.
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The problem is that Nidec has tuned the cooling fan to Nvidia’s specs. It does not come standard with his 120mm design. Therefore the mounting holes are different. Additionally, the AD4A31K04 and AD4A31K05 are not 120 mm cooling fans either. According to one Taobao merchant, the size is his 115 x 115 x 12.5 mm, so DIY enthusiasts should 3D print his own bracket from plastic or other types of materials. As another his Chiphell forum, it’s a challenge. user (opens in new tab) It states that the fan has a diameter of 116m with a reserved space of about 2mm. As a result, the frame thickness is limited to 1mm.
Nidec does not list the AD4A31K04 or AD4A31K05 on their website, so we have gathered the specifications from various Chinese vendors on the market. The base of the fan is made of metal, while the shell of the motor is made of aluminum alloy. The fan has a maximum speed of 3,300 RPM and can go up to 0.63A. However, 1 owner (opens in new tab) Some samples claim it can reach 3,500 RPM. In any case, the AD4A31K04 and AD4A31K05 are very fast spinning fans.
However, it consumes considerable power. Cooler Master Mobius 120P ARGB all disco lights are rated at 0.48A, AD4A31K04 and AD4A31K05 are up to 31% higher. A traditional 4-pin fan connector is good for up to 1A, so this is not a big issue.
The AD4A31K04 or AD4A31K05 draws power from a special ribbon cable with a 6-pin layout. The fan connects directly to Nvidia’s PCB, but requires a custom 4-pin adapter to connect to the motherboard’s standard fan connector.
Given the overall cost and complexity of an axial fan mod, it’s probably more viable to buy a CPU cooler, AIO liquid cooler, or a premium cooling fan for your case. Still, it’s always cool to see DIY enthusiasts thinking outside the box.
