Steam Machine LP - A 3L Custom 3D Printed Steam Machine
Looking for input (especially from electrical engineers) on my planned SteamOS build around the Lenovo ThinkCentre M90q Gen 6 and RX 9060 XT 16GB. Specifically, I want to make sure I have a good understanding of how everything works together electrically:
The build starts with a Lenovo ThinkCentre M90q Gen 6 - Intel Ultra 5 235T with 8GB RAM 256GB SSD
I am going to throw another 8GB stick of RAM into it for dual channel 16GB
And an Intel BE200 and antenna kit for WiFi 7 support
Now comes the fun part. Most people aren’t aware, but many of the Lenovo ThinkCentre models come with a proprietary PCIe x8 4.0 slot that can be adapted to a regular x16 slot, albeit at x8 speeds
I plan to use this adapter with a PCIe x16 4.0 riser Now comes the tricky part. Most people would likely power the Lenovo from its original proprietary PSU input. But I want to try to make this as compact as possible. The GPU already needs 12V external power, so I figured I can do the following:
- Buy HDPLEX 500W GaN PSU
- Use that to power the GPU. The Lenovo however expects 20V power, not 12V power. So I need a boost converter - Model # ATO-093620-240W
- This provides up to 12A at 20V, which even exceeds the 230W power adapter that ships with the computer. I am hoping to wire this up to the EPS 12V output of the HDPLEX. Considering 12A @ 20V is equivalent to 20A @ 12V, and the EPS 12V connector can do 7A @ 12V on each pin (7A * 4 pins = 28A @ 12V) I believe this shouldn’t be an issue. The Boost Converter will be wrapped in kapton tape and stuck in the void where a normal single slot LP card would sit (space is not needed due to using riser).
I have attached 3D models of the orientation I expect to connect everything in and a wiring diagram to boot. Please let me know if I have made any fatal errors in my design and I will be sure to make changes. I plan to create a custom 3D printed enclosure around all the hardware, waiting for real hardware before I fully design the exterior
My 3D design fits into a 76.7mm x 214mm x 185mm footprint for a total volume of ~3.075 liters including built-in PSU, even less volume than Steam Machine (3.8L). Yes, I know this machine is more expensive, but you could theoretically go for an older model of the M90q that costs less and the 500W PSU is a bit overkill. Can cut cost by using Lenovo power brick and going for something in the 250W range (which my design will also support). I will also be embedding a Steam Controller puck inside the PC. I also have plans to use HomeKit/Homebridge to have the Machine turn on my TV and switch to the correct input when the computer wakes up to emulate the on-off behavior of CEC as best I can.
Bring Up Process:
- Boot Lenovo stock with stock power supply
- Check compatibility with 2nd stick of RAM
- Connect HDPLEX to GPU, connect both risers to Lenovo and GPU, run GPU test
- Install SteamOS, validate all functionality
- Remove RAM, wire up HDPLEX EPS to input of boost converter, wire output of boost converter Lenovo power input (either directly soldered or soldered to repurposed barrel jack., validate functionality
- Take measurements of all parts laid out in compact format
- Design 3D enclosure
- Likely add finishing touches, i.e. front panel I/O, power button, way to easily remove Steam Controller puck
- Print enclosure and assemble
| Type | Item | Price |
|---|---|---|
| Mini PC | Lenovo Thinkcentre M90Q G6 Tiny PC Intel Ultra 5 235T 8GB RAM 256GB SSD | $601.99 @ EBay |
| Memory | Crucial 8GB (1x8GB) DDR5-5600 PC5-44800 262-Pin SO-DIMM | $75.00 @ EBay |
| Video Card | PowerColor Reaper AMD Radeon RX 9060 XT 16GB GDDR6 | $469.99 @ Amazon |
| Power Supply | HDPLEX 500W GaN AIO | $175.00 @ HDPLEX |
| Lenovo Riser | New Genuine Lenovo ThinkStation P3 Tiny P360 Tiny PCIex16 Riser Card 5C50W32107 | $69.95 @ EBay |
| PCIe 4.0 Riser | 300mm PCIe 4.0 X16 Riser Cable | $38.99 @ Amazon |
| WiFi Card | WiFi 7 Wireless Card Intel BE200 NGW | $32.28 @ Amazon |
| WiFi Antenna | WiFi Antenna Tiny 6 7 8 for Lenovo ThinkCentre M90q | $14.85 @ EBay |
| 12V to 20V Booster | ATO-093620-240W | $68.41 @ ATO |
| Prices DO NOT include shipping, taxes, rebates, and discounts | ||
| Total | $1,546.46 | |
| Generated by /u/YourMomTheRedditor 2026-06-29 02:25 EDT-0400 |
Thoughts? Any feedback is appreciated but please be gentle.