After letting the black smoke out of my AMD FX8120, I upgraded to the FX8320 and OpenSuse wouldn’t boot normally; something about kernel panic, different CPUID, and an automatic reboot after 30 seconds.
It was a long and windy path, which included an attempt to recompile the kernel and eventually upgrade from 13.1 to 13.2 so it could (hopefully) do that itself, no dice.
Had no problems starting up using the 1st recovery mode, but the resolution was minimal so the system wasn’t usable.
Comparing the recovery options to normal, one option stood out: processor.max_cstate=1. Adding that to my boot options resolved (w/high res) so I persisted that in my boot options.
I plan to restore an image of my install since this one got beat up, but I’m hoping for (1) a more direct way to resolve once I restore (2) an explanation on why a minor cpu upgrade would derail the OS and (3) and why the powersave option (?!) allowed the system to load successfully.