A programming, electronics, and retro enthusiast has showcased an open-source Intel 486 motherboard that they claim was “made from scratch” in under six months. The M8SBC-486 isn’t based on existing designs, but on previous experimental work by the maker, Maniek86. This real Intel 486 CPU packing project originally began with the goal of creating a system that could run Linux and Doom. However, Maniek86 excelled themselves and noted that the system also runs various flavors of DOS, Windows 3.1 (kinda), various programs, and games like Prince of Persia and Wolfenstein 3D.
Another thing that helped Maniek86 was a relaxed attitude to compatibility. The target was ‘simply’ to be able to run Linux and Doom on the assembled machine. Providing a speedier route to this goal, the dev’s chipset (Codename Hamster 1) was implemented in an FPGA, as were some other essentials like input device controllers, CMOS RTC, and storage. PCB prototyping and manufacturing outfit PCBWay was also praised for its help and support.
Maniek86 also didn’t care too much about functions that weren’t essential to the original goal. Thus, “the secondary PIC and DMA” are missing. Check out the list below for the full specs of M8SBC-486, as of January 14, 2026.
- 150 x 150mm 4 layer PCB. Custom hole placement! (a bit smaller than the 170mm square Mini-ITX standard).
- PGA-168 socket for 5V 486 CPUs. FSB currently runs at 24 MHz, meaning that DX2 CPUs work at 48 MHz
- Currently operating at 24 MHz FSB
- Xilinx Spartan II XC2S100 FPGA as the chipset. Codename "Hamster 1"
- 4MB of SRAM
- 256KB (224KB accessible) ROM for BIOS
- 8254 Programmable Interval Timer (PIT)
- 8259 Programmable Interrupt Controller (PIC)
- Two 16-bit ISA slots
- PS/2 keyboard port. Controller is implemented in the FPGA
- Simple CMOS RTC and CMOS storage. Implemented in the FPGA too
- ATMega128 as reset circuit handler, nonvolatile CMOS storage and bitstream loader.
Since this project is open source, it might be interesting for like-minded readers to tinker with the source files and even build their own M8SBC-486 derivative design. Maniek86 admits that “There are still many issues,” but is gratified that the capabilities of this motherboard exceeded the initial goals already.
Meanwhile, the open source nature of the project beckons contributions. “I am pretty sure that this work could be used to build something more robust and stable or even to develop fully custom-made boards for other x86 CPUs,” says the maker. We’d also like to see the ISA slots become more useful, as graphics cards have poor or glitchy performance, sound cards are almost 100% incompatible, and a swathe of other cards are untested and not likely to work without ISA PnP feature support and DMA.
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