Quote Originally Posted by The Verge
Microsoft’s Xbox Cloud Gaming service (xCloud) is now fully powered by custom Xbox Series X hardware. Microsoft tells The Verge it recently completed the upgrade, which improves both framerates and game load times for players streaming Xbox games over the web.

While Microsoft has moved Xbox Cloud Gaming to 1080p and 60fps streams in recent months, the company has yet to unlock the full potential of custom Xbox Series X hardware to deliver 4K streams.
Xbox Cloud Gaming is now fully powered by faster Xbox Series X hardware - The Verge