I was talking about uploading a terabyte. Also on my connection, when one person is uploading, download speed falls from 25Mbps to a crawl. I think it's something to do with coax being half-duplex. My family wouldn't put up with slow internet for the 24.73 hours it would take to upload 10GB, let alone the two months it would take to push a terabyte.
If I had to move that kind of data, I would mail storage media.
A dial up modem can do gigabytes per month...