My memory is that the pentium pro had a common memory config of 256MB, way below what modern installers are going to expect. I'm sure you can get linux to install on 256MB, but I doubt it's going to work on the current RHEL/SUSE/Ubuntu installers.

Not to mention various drivers have gone without maintainers and pulled from the upstream linux kernel.

Not to mention dropping IA32 and related PAE support.