All old xboxes are supposed to keep track of the time (stock dash) for ~3 hours.
360's don't have a clock cap since MS initially thought everybody would be connected to the Net anyway.
Seeing how both the Xbox and the 360 sync time upon first connection, battery backed time or cap backed time is becoming pointless ;p
This is also true for other consoles.
Wii/PS3 where also connected to the Internet for most of the times.
XBone/PS4/Wii U, same story.
360's don't have a clock cap since MS initially thought everybody would be connected to the Net anyway.
Seeing how both the Xbox and the 360 sync time upon first connection, battery backed time or cap backed time is becoming pointless ;p
This is also true for other consoles.
Wii/PS3 where also connected to the Internet for most of the times.
XBone/PS4/Wii U, same story.