Our two-way transfer rate averages from 1GB to about 10GB per hour per account (240GB per day per account).
Our one-way migration transfer rate is up to 1TB per day per account.
However, in many cases, especially if an account has a large number of small files and a large number of folders, it is very difficult to predict how long a given transfer will take. Depending on the number of directories, the number of files, the size of those files, and the source/destination, it can sometimes take longer than expected to move your data. Our servers do not have any limits, and speed can reach up to 2TB/day per account.
What may be surprising is how large of an impact factor other than the size of the data you are syncing can have. For example, it is not uncommon for 1-5 seconds of overhead per file to be copied (target service needs to catalog this file, index it, verify it, etc.). If you are trying to move 200,000 files, this would be 200,000 – 1,000,000 seconds or up to 11 days of overhead alone!
Furthermore, some cloud apps and cloud storage providers have throttling limits (for example, Microsoft OneDrive), which can influence your transfer speed.
For Dropbox, the performance may start to decline when you store above 300,000 files as described here: https://www.dropbox.com/en/help/39.
Dropbox Business also limits 1 million API calls/month for data transport. And each call to create a file requires 1 to 3 API calls meaning that the maximum speed is about 300,000 to 1,000,000 files per month. For more details about this Dropbox limitation please go here: https://www.dropbox.com/business/plans-comparison
We are constantly working hard on some exciting state-of-the-art algorithms, both with our partners and on our technology — to make sure your data is replicated as quickly as possible and give you as much visibility into your transfer.