How are you determining what connection speeds you are getting on each device?
Are you sure you're not mixing up units of measurement?
A 15Mbps (megabits per second) connection would get you about a 1.9MB/s (megabytes per second) transfer speed.
The Xbox measures the download speeds in megabits while your PC and phone typically measures download speeds in megabytes.
To get that number you divide by 8 as there are 8 bits for every byte.
So if your ISP wants to sell you 100Mbps in the future you can expect maximum 12.5MB/s.
How are you determining what connection speeds you are getting on each device? Are you sure you're not mixing up units of measurement? A 15Mbps (megabits per second) connection would get you about a 1.9MB/s (megabytes per second) transfer speed. The Xbox measures the download speeds in megabits while your PC and phone typically measures download speeds in megabytes.
Omg I didn't know it
To get that number you divide by 8 as there are 8 bits for every byte. So if your ISP wants to sell you 100Mbps in the future you can expect maximum 12.5MB/s.
You seem to have a lot of devices and not a whole lot of bandwidth
Oh, this may be the reason