June 27, 2026
Description
This model is a case for Sixunited AXB35 boards with up to Ryzen AI Max+ 395 which is used in mini computers such as the Bosgame M5 or GMKtec EVO-X2.
The biggest problem of these cases is the thermals and the noise level. The original models use a relatively small heatsink and loud blower fans to cool the chip, which is often not sufficient. This model is a complete overhaul that completely strips the mainboard out of the original case to allow mounting full size 120mm CPU coolers on the bare SoC. The bottom part of the case reinforces the board to allow even heavy, quiet oversized coolers like the Peerless Assassin 120.
In my configuration of this case, the SoC temperature is kept well below 70 degrees Celsius in balanced mode with minimal noise. The bottom fan keeps auxiliary components cool, the side panel fans cool the VRMs. If you want to use performance mode: This cooler has no issues at all to cool the SoC. However, VRMs can get very hot like this, so make sure you have adequately sized heatsinks mounted on them and the case airflow is enough.
This design is not 100% polished, but is very functional. It has some minor issues (see known issues at the bottom of the page) that make assembly or printing a little harder than it could be, but it works really well for me.
Bill of materials, non 3D-printed
- 1x 120mm CPU-Cooler (including thermal paste and LGA 1200/1700 mounting kit)
- 4x 40mm M3 screws
- 4x M3 heat threaded inserts
- 3x 120mm slim fans (15mm thick, I use Arctic P12 Slim)
- 4x Standard Fan screws (should come included with the 120mm fans)
- 3x 4-pin Micro JST 1.25mm to 4-pin 2.54mm PWM fan cables (needs to be DIYed, see instructions below)
- M.2 heatsinks for the RAM chips (need to be cut to size) or something comparable (e.g. these https://www.amazon.com/Atdcoek-Cooler-Heatsink-Thermal-Silicone/dp/B0FHFP4Y9T)
- Heatsinks for the VRMs (e.g. https://www.amazon.com/Heatsink-Anodized-Aluminum-Regulators-9x9x12mm/dp/B0DLN18WX9)
- Glue to fix 120mm slim fans to the side panels
- (Optional) 2x 20-25cm MHF4 to RP-SMA cables to route the antenna outside of the case
Choosing a CPU cooler
The principle behind this whole case is that the AXB35 board has an LGA 1200/1700 compatible mount, which allows mounting some standard Intel CPU coolers onto the SoC. In my case, I used the Peerless Assassin 120mm. Some parts, like the side-panel fan inlet and the cooler spacers, are therefore tailor-made for this specific fan. However, the case can be easily adapted to allow being used with other fans as well.
If you want to use another cooler, make sure it fits within the case dimensions. Ideally, compare it's size with the Peerless Assassin - if its smaller, it will fit for sure, if a dimension is bigger, it can lead to problems.
Use a cooler with good clearance below it - that makes it easier to mount heatsinks for the exposed RAM and VRM modules later.
Make sure the cooler is LGA 1200/1700 compatible AND COMES WITH THE RIGHT MOUNTING KIT. I originally wanted to use another cooler, but it lacked the mounting kit, so I had to disassemble another main board instead. Don't be dumb like me.
Print instructions
Some of the parts have be able to withstand higher temperatures than standard PLA. Print them in PETG or better. If not specified differently, print in PLA with 0.2mm or 0.24mm layer height and without supports.
axb-case-bottom-OuterShell(-NoAntenna):
Print in PETG or better. The normal variant does have mounting holes for a wifi antenna, the NoAntenna version does not.
axb-case-bottom-BottomPlate + axb-case-bottom-FanGrill:
Print in PETG or better. This is one part, separated into two files. Combine them and print the bottom plate in default settings, the fan grill with the same settings as the side panels.
axb-35-case-top-TopShellBody:
Can be printed in PLA, but PETG is safer.
axb-35-case-top-IOPanels:
Print with 0.12 - 0.20mm layer height. Orient this print such that the little pillars of the IO cutouts show upward and the edges of the part are floating. This part is not ideal yet and requires supports for the floating edges. The support needs to be well dialed in, otherwise the parts cannot be well connected. If you can, use a different interface material that does not stick, such as PETG for PLA or the other way around.
axb-35-case-top-PowerButton, axb-35-case-top-ResetButton:
Use 0.12 mm layer height with concentric top layer infill.
Instead of the printed power button, you can use the original one. It requires snipping off the extension thing of the button though, so if you want to be able to reverse this case mod, use the printed button.
axb-35-case-sidePanel(-*):
Print in PETG or better. These are fan grills, so they must let air through. Print with:
- 3 wall Loops
- 0 top shell layers
- 0 bottom shell layers
-Â 50-60% sparse infill density (depending how fine you want the grill to be)
- Grid sparse infill pattern (others possible, but haven't tested, honeycomb could be nice for example)
Print:
- 2x SidePanel120mmFanBracket
- 1-2x SidePanel (2x if you don't use the inlet)
- 1x SidePanelPeerlessAssassinInlet if you have a Peerless Assassin Cooler
axb-35-lga-1200-spacer-PeerlessAssassin:
Print in PETG or better. Use 100% infill or fill the part with walls. Needs be solid! Print 4x.
This part is tailor made for the Peerless Assassin 120. If you use another cooler, the mounting height will most likely be wrong. Therefore, a simple SCAD file is included (axb-35-lga-1200-spacer.scad) to make your own spacers with different heights. BE VERY CAREFUL WHEN TESTINGÂ THESE! Only apply very little force when mounting the cooler to make sure the die does not crack.
Build instructions (fan adapter cables)
Unfortunately, the axb 35 board uses small non-standard PWM fan connectors that do not even have the default pin order. The connectors on the board are 1.25mm micro JST, while the standard 4-pin PWM connectors are 2.54mm and much bigger. There are no adapter cables that can be outright bought, so you need to make them yourself.
Original cable order is:
red -> 12V
blue -> PWM
black -> GND
yellow -> tacho
Standard 4-pin PWM is:
black -> GND
red -> 12V
yellow -> tacho
blue -> PWM
Buy a micro JST 1.25mm crimping kit like this https://www.amazon.com/Kuosbiu-Connector-Connectors-Premium-Pre-Crimped/dp/B0CS9GFVCW or comparable prepared cables. Then, you can use sacrificial fan cables and solder the leads together, or, if you don't want to solder, use GPU 4-pin adapters like these https://www.amazon.com/CRJ-4-Pin-Adapter-Sleeved-Graphics/dp/B07Q5BTTDX which adapt from an intermediate size (2mm) to standard PWM. The 1.25mm pins should fit into the 2mm header and you can use heatshrink sleeves to fix it in place.
Tips:
If you use colored cables for the 4pin PWM side, it's easier to not mess up
Use small heatshrink sleeves around individual cables to avoid shorts if you solder
Use the original blower fans as reference to build the micro JST connector correctly
Assembly instructions
Prerequisites:
Glue the 120mm fans to the SidePanel120mmFanBracket parts. Make sure one fan is mounted as an exhaust, the other as intake.
Mount the 120mm bottom fan to the bottom shell
Insert the 4x M3 heat threaded inserts into the axb-35-case-top-TopShellBody pillars.
Remove the AXB-35 board from the original case and remove the original heatsink. Clean the SoC thoroughly with Isoprop Alcohol or similar.
M.2 heatsinks are cut to size to fit flush over the RAM chips
(Optional) If you want to user the original power button, snip off the extension thingy so it becomes symmetric again (compare to the power button stl if in doubt what I mean)
Steps:
Place the axb35 board on the bottom shell with the SoC side upwards, M.2 drives downwards. This supports the board to handle the added weight of the heavy cooler.
(Optional) You can use M3 nuts and the M3 screws to mount it in place temporarily, which makes it a little easier to handle.
Place the M.2 heatsinks on the RAM chips (without the glue pads for now). Dry fit the cooler to see if the clearance for them is enough. If not, you might need to remove some fins from them with a saw or Dremel to make them fit (that was necessary for me)
Once everything fits, mount the M.2 heatsinks to the RAM chips.
Mount the cooler on the board. BE VERY CAREFUL WHEN DOING THIS! Only apply very little force when mounting the cooler to make sure the die does not crack. Apply the force evenly and only do half turns or less with the screw driver for each screw until proceeding to the next one.
Mount the VRM heatsinks
Connect the cooler fan cable(s) to each other and to the boards CPU FAN 1 connector
(Optional) if you have temporarily mounted the bottom shell to the mainboard for cooler assembly, unmount it
Place the power button and reset button into the IO panel. There is some tolerance, make sure they do not fall out
Place the IO panel with the buttons on top of the of the board
Place the top shell (TopShellBody) on top of the assembly
Hold the assembly together and carefully flip it upside down.
(Optional) If you use the wifi antenna cables, connect them and mount them to the buttom shell. If you use the original antennas, glue them to the sides
Connect the fan cable of the bottom fan and fit the bottom plate
Carefully align everything. Make sure the mainboard is flush against the buttons such that they can be pressed without wiggle, but do not already press the buttons by default
Mount the assembly together by fitting the bottom feet and screwing the M3 screws trough the whole assembly. Make sure everything is aligned properly. Do not hesitate to unscrew the feet and re-tighten them to realign the assembly if necessary
Carefully flip the case again and place it on the feet.
Connect the side panel fans to the boards CPU 2 FAN connector
Snap in the side panel with front fan. THIS SHOULD BE THE INTAKE!
Snap in the side panel with back fan. THIS SHOULD BE THE EXHAUST!
Snap in the left panel (with the fan inlet if you use the Peerless Assassin)
Snap in the right panel
You're done!
Known Issues
This design took a lot of time and lots of iterations, hence it is, even after a lot of work, not 100% polished. There are some things to improve:
fans need to be glued to the side panels, I haven't found a good looking alternative yet that works
one part (the IO panel) requires supports that are well dialed in or, even better, a different support interface material (e.g. PETG for PLA). It's not a huge area and only a single layer, but if the supports are bad, the parts dont fit together
the power button can get stuck if the board is not mounted flush in the direction of it
the power button lighting is not 100% even
it's a little finicky to align everything
The area around the WiFi antenna RP-SMA mounts is a little thick, which can cause Antennas to not be perfectly attached
License:
Creative Commons — Attribution — Share Alike
QuadratClown
