2tb Mycloud to ex4100 transfer

I have a WD Mycloud which is full with 2tb. Ive picked up a WD mycloud ex4100 .
What is the quickest way to copy across 2tb of data?
I copied and pasted yesterday but after 16 hours it is on 5% , so based on that is it really going to take 294 hours to finish??

I have since tried delta copy, rsync but you need to be a computer genius to use them