With the recently-launched Ubuntu 25.04 and Fedora 42 Linux distributions I've been seeing very healthy competition on Intel and AMD x86_64 hardware between these two leading Linux operating systems. But, surprisingly, after evaluating the AArch64 performance I was surprised to find Ubuntu 25.04 delivering a decisive advantage over Fedora 42 when testing on Ampere Altra using a System76 Thelio Astra workstation.