All it takes is a €50 mod to keep this AMD GPU chill and in complete silence

An RX 6400 GPU mod for passive cooling
(Image credit: Reddit - Revoccases)

There's an entire niche of our hobby dedicated to building quiet, if not silent, PCs. I absolutely love it. It's not just that these parts are passively cooled and require no moving parts, it's also how properly awesome they all look. 

Take this passively cooled AMD Radeon RX 6400 graphics card from Reddit user Revoccases (spotted by our pals at FanlessTech), it's gorgeous. It's also massively oversized, as you might have noticed, and the actual GPU is hidden by a heatsink loosely three times its size. But it's all in the name of silent operation and thermal performance.

This card is a humble RX 6400, which comes with just 12 Compute Units for a total of 768 shader cores. As such, it's not a wildly powerful gaming GPU, but you'd be very hard pressed to keep an RTX 4090 cool without any fans whatsoever. Let's be real, for this sort of passive mod we're looking at something more moderate, and with a typical board power of 53W, and the RX 6400 is just that.

Revoccases goes through all the steps required to build out this mod over on the smallformfactor.net forum. First they started with a low profile card and then machined out a 3mm copper coldplate to cover the GPU and memory. The GPU and memory are at slightly different heights, so there are some thermal pads required to get proper contact.

The actual heatsink part is the Accelero S1, a sink and heat pipe cooler that's been around for a decade and a half, which is then soldered onto the coldplate.

The result is a card that, during a one-hour stress test in the Heaven benchmark, reached just 60°C via the hotspot reading on the card, and only 54°C from the GPU temp sensor.

Revoccases told me that the entire mod cost around €50, though you'd need to add the cost of the RX 6400 to that if you intend to mod that exact card yourself. Thankfully, they've also uploaded drawings of the coldplate over on the forum post for all to use.

Your next upgrade

(Image credit: Future)

Best CPU for gaming: The top chips from Intel and AMD
Best gaming motherboard: The right boards
Best graphics card: Your perfect pixel-pusher awaits
Best SSD for gaming: Get into the game ahead of the rest

The whole build is nicknamed the Kalmx AMD Edition, a nod to one of the very few truly passive graphics cards in recent years, the Palit GeForce RTX 1650 KalmX. They just don't make many like it anymore, despite there being a couple of cards suitable, as Revoccases tells me.

"The RX 6400 and [RTX] A2000 are perfect for passive cooling but it seems too much of a niche these days for manufacturers to offer something like the KalmX to end customers."

It's a shame, but this project just goes to show you don't necessarily need a manufacturer to do the work for you. But you will need to be at least a little bit handy machining metals, or know someone who is.

Now to pair one of these passive GPUs with Noctua's NH-P1... it won't be powerful, but it will be perfectly silent.

Jacob Ridley
Managing Editor, Hardware

Jacob earned his first byline writing for his own tech blog. From there, he graduated to professionally breaking things as hardware writer at PCGamesN, and would go on to run the team as hardware editor. He joined PC Gamer's top staff as senior hardware editor before becoming managing editor of the hardware team, and you'll now find him reporting on the latest developments in the technology and gaming industries and testing the newest PC components.

Read more
A gaming PC build using the Be Quiet Shadow Base 800 FX chassis, an Intel Core Ultra CPU and an RX 7900 XT GPU.
This no-vidia gaming PC is a great example of how small design decisions can make it feel like you're building a PC on easy-mode
A screenshot of a video on BiliBilli showing an air conditioning unit attached to a PC with Nvidia, AMD and Intel stickers.
The definition of overkill: Cooling an RTX 4090 to a claimed 20°C with a household air conditioning unit
Three RTX 5090 graphics cards on display at the Asus suite, CES 2025.
The RTX 5090 Founders Edition might be svelte but the Asus ROG Astral cards are absolute chonkers
The Asrock Deskmini X600 open
ASRock DeskMini X600 review
Four-slot Nvidia GPU
Quad-slot prototype enabled Nvidia to achieve 'mission impossible' with RTX 5090 GPU's dual-slot cooler
A gaming PC with RGB lighting enabled on a desk.
This gaming PC build smashes together the very latest components but if I did it again, I'd do it differently
Latest in Graphics Cards
A side by side comparison of two Asus Q-Release systems, with the original design on the top and the bottom showing the apparently new design.
Asus appears to have quietly changed the design of its Q-Release PCIe slot after claims of potential GPU pin damage
A Colorful RTX 5080 and its box
Three lucky folks in India can win the dubious honour of buying an RTX 5080 GPU at Nvidia MSRP
Jensen Huang, co-founder and chief executive officer of Nvidia Corp., speaks while holding the company's new GeForce RTX 50 series graphics cards and a Thor Blackwell robotics processor during the 2025 CES event in Las Vegas, Nevada, US, on Monday, Jan. 6, 2025. Huang announced a raft of new chips, software and services, aiming to stay at the forefront of artificial intelligence computing. Photographer: Bridget Bennett/Bloomberg via Getty Images
Group allegedly trying to smuggle Nvidia Blackwell chips stare down bail set at over $1 million
Nvidia RTX 5090 Founders Edition graphics card on different backgrounds
AI will be crammed in more of the graphics pipeline as Nvidia and Microsoft are bringing AI shading to a DirectX preview next month
Nvidia RTX 50-series graphics cards alongside an RTX 4090
Nvidia says it's sold twice as many RTX 50-series cards as RTX 40-series in the first 5 weeks. I'd bloody well hope so given there was essentially just the RTX 4090 for competition
AMD Radeon RX 9070/9070 XT graphics cards with artistic renders of reference design cards circled
Looks like a reference design AMD RX 9070 XT card has shown up in China, but let's not get carried away with thoughts of MBA cards just yet
Latest in News
Closeup of the new Copilot key coming to Windows 11 PC keyboards
Microsoft co-authored paper suggests the regular use of gen-AI can leave users with a 'diminished skill for independent problem-solving' and at least one AI model seems to agree
A lolporrit squeals in excitement while being driven in a moon buggie in Final Fantasy 14: Dawntrail, patch 7.2.
Final Fantasy 14 patch 7.2's trailer has me finally hyped to get stuck back in—and to go to the moon and pilot some mechs, because why not
A pink GameSir Nova Lite, and a purple 8BitDo Ultimate 2C float in a teal void.
Hall effect controllers are so cheap now I’ve got a deal for you AND your player two
Peely from Fortnite with banana-fied Wolverine claws.
Fortnite comes to Snapdragon: Epic Games announces upcoming Arm support for its Easy Anti-Cheat software
Texas Instruments MSPM0C1104 tiny chip
World's smallest microcontroller looks like I could easily accidentally inhale it but packs a genuine 32-bit Arm CPU
Varjo Aero
Varjo Aero VR headsets seem to be not working on RTX 5090s, and its community is opting for strange solutions while waiting for an Nvidia driver release to fix it