Hi,
We apologize for the inconvenience this may have caused you.
Slow upload speeds can be an issue with a user's Internet Service Provider, network card, connection type, size of upload, and other things. If the folder is getting used, then the server will throttle the speed to ensure it is not overloaded for others.
I would have you follow the suggestions provided by Dan T on December 21, 2013and see if it fixes the issue.
If the issue persists, we recommend you to contact Answer Tech team since we have a dedicated support team for the sync issues, they will be able to help you with this issue.
If you face any difficulties reaching out to them, please let us know.
Thank you.
Link is broken.
I have the same problem. Dropbox upload rate is 5-10 times faster.
I hope Microsoft will solve that problem. Because the other things are fine. Office 365... etc.
Thanks.