I guess the resynchronisation time is taken up mostly by Dropbox reading and hashing all 5 GB to detect changes? Just that it considers each file as a series of

I guess the resynchronisation time is taken up mostly by Dropbox reading and hashing all 5 GB to detect changes? Just that it considers each file as a series of contiguous chunks and should only transfer those chunks that have changed. A bit like how BitTorrent works.