https://wccftech.com/xbox-series-x-gpu-more-performant-amd-navi/

The Xbox Series X console design is unlike anything we have seen for consoles up until now, and it's likely that the bulkier design is due to increased power consumption, rather than the actual size of the components. The increased power consumption is a given due to how powerful the GPU will be, as it will more performant and feature-rich than any Navi component released by AMD this year, according to a fresh analysis of the upcoming console.

Digital Foundry released today an in-depth analysis of the next-generation Microsoft console, highlighting how the console's GPU frequencies are likely higher than those seen in AMD's Navi based GPUs due to everything we know so far.