Office 365 Backup: Auxiliary accounts, cloud to cloud
When backing up from Microsoft Office 365, SharePoint Online and OneDrive, Microsoft will place a throttling limit on the download so they can keep consistent access to the data. This throttling metric is provisioned on a per-account login to a single site and is determined by Microsoft. It includes the level of plan you pay for, the size of your organization and the amount of data your site contains. The exact numbers for these parameters are not posted publicly, but you can expect that a company with sub 100 E1 licenses will be on a lower speed tier to a company with over 1,000 E5 licenses.
Curious about Veeams solution?