The only thing I can find from my testing is that the office 365 / exchange online servers cap your upload or they need a better pipe. My network resources are not even close to being exhausted nor are my systems yet it is taking a ridiculous amount of time to upload these PST files. I already know that MS is going to point the finger at our systems or network so here are some figures that I pulled.
As you can see from our firewall the current upload speed to MS servers is 67 KB/s.
Our bandwidth capacity currently is about 60 mbps which transates to around 7500 KB/s.
Here is a current shot of system performance on the system doing the migration
Don't even tell me I need more RAM. I could put 92GB into this system and it wouldn't make a difference. Please MS admit that you have a problem and do something about it. I don't see how we can sell this if enterprises can't access their old email while we transfer them to the cloud. If you really really think it's something else I would be happy to do any test you would like otherwise please give the community a realistic expectation of improvement with your service.