My 2TB is creating a backup and is running about 10 mg per second

Why? I have windows 8.1 , I backed up my C drive with no issues. I am now backing up my D drive and it is suddenly running very siow.  In 10 hours it has backed up 166  Gb.  My C dirve which has 550 gb of data only took about 3 hours.

Anybody know why?

It’s worse now about 10 mg every 8 seconds.


Do you encounter the same speed issues when performing a manual file copy instead of using automatic backup applications?