Editing Atari PC5 (section)

== Overview ==
Unlike the [[Atari PC4|PC4]], which used an Atari-designed motherboard, the PC5 was built around a third-party American Megatrends (AMI) 386XT Series-4 motherboard. This was a practical decision, as designing a 386-class motherboard in-house would have been costly. The AMI board featured a socket for an Intel 387 co-processor and supported CPU upgrades up to a 386DX-25.

The PC5 was notable for being the only Atari PC offered with a Unix-based operating system option: "Eurix", a German-localised version of Unix System V/386 Release 3.2, was available as an alternative to the standard MS-DOS and Windows/386 configuration. This positioned the PC5 as potentially suitable for business and technical workstation applications.

One downside of the AMI motherboard was its lack of onboard RAM expansion slots — all memory was handled through a 32-bit memory expansion card, which was typically limited to 2 MB on the 16 MHz model and 4 MB on the 20 MHz model.