Intel i386DX 16MHz or 20MHz
2 or 4 MB of RAM
WD VGA Plus 16 256k VGA Graphics Adapter
Epson SD-680L 5.25″ 1.2MB Floppy Drive or 1.44MB Floppy Drive
Seagate ST-277R 66MB RLL Hard Drive
Microsoft MS-DOS 3.3 and GW-BASIC 3.2
Microsoft Windows/386 version 2.0
“Eurix” German localised version of Unix System v/386 Release 3.2
Mitsumi KPQ-E99YC AT Keyboard
Mitsumi 2 Button Serial Mouse
The motherboard used in this system is not an Atari proprietary motherboard it is actually an American Megatrends (AMI) 386XT Series-4. As well as having a NPU socket for a 387 coprocessor upgrade, it is also possible to upgrade the CPU to a 386DX-25. While I have been unable to locate the detailed specifications for the Series-4, it is practically identical to the Series-6.
One of the downsides with this particular motherboard they used is that it has no onboard RAM expansion slots. RAM is all handled through a 32 bit memory expansion card which was generally limited to 2MB on the 386 16 and 4MB on the 386 20.