With the latest update in test, members of the Xbox Insider program had a welcome surprise: the console's "cold boot" times (i.e. from the full shutdown state) were greatly reduced on Xbox Series X and S, going from about 11 seconds previously to get from the initial animation to the player's login, at 6 seconds, a reduction of almost 50%.

Here's this timeline as measured by The Verge reporter Tom Warren:

However, this time is only part of the complete boot process, which goes from pressing the power button to loading the Home; the other parts of the boot were not optimized, so the total time dropped from about 20 to 15 seconds, an improvement of about 25%."

Microsoft had not announced this change, but after players noticed this novelty, it was confirmed that the team has worked on this optimization, also reducing the duration of the initial animation.

The improvement, however, is not limited only to the already very fast next-generation consoles: even the console of the Xbox One family have received an improvement in power-up times, although for now it has not been measured.

Soon, probably with the August update of the console, all players will receive this improvement: an extra incentive to keep the console in power saving mode, since it will now update faster and will still remain updated.