Maintenance for the week of December 23:
• NA megaservers for maintenance – December 23, 4:00AM EST (9:00 UTC) - 9:00AM EST (14:00 UTC)
• EU megaservers for maintenance – December 23, 9:00 UTC (4:00AM EST) - 14:00 UTC (9:00AM EST)
You can open up the Resource Monitor in Windows and filter by eso.exe to get the current Bytes/second. On startup it's quite high, ~1100 - 1900. After a minute or so it declines to ~500. So, given that 500 B/s, 60 seconds in a minute, 60 minutes in an hour roughly equates to ~1.8M and can get as high as ~7.2M per hour. A relatively slow network should still be able to handle that.