Wow! A TB drive is pretty big for AC backups. So, for the purpose of this discussion, can we just talk about the computer backup? Thanks.
From what I am reading, you are backing up 4.5GB of data to an external drive in four minutes. Can you answer a few questions?
First, is the external drive connected with USB 2.0 or USB 3.0 or are you using eSATA and, if so, what speed?
Second are you doing a:
Full backup
Differential
Incremental
Single Instance Store
Deduplication
I am also confused by the 70,838 files and 245 files? Which is it?

Thanks. I am just curious.