The Xbox One was the first Xbox console to use a custom AMD x86-64 processor. Its system-on-chip combined eight Jaguar CPU cores with a Radeon-derived graphics processor.
This marked a major architectural change for Microsoft. The original Xbox used a Pentium III-based processor, while the Xbox 360 used a custom PowerPC-based triple-core CPU. The Xbox One instead adopted the x86-64 instruction set used by modern personal computers.
The Xbox One’s processor was designed by AMD and customized for Microsoft’s console. Later Xbox Series consoles also use custom AMD Zen 2-based x86-64 processors, but they came after the Xbox One and therefore were not the first Xbox systems with that architecture.