Proximity to NCBI may not necessarily give you the fastest transfer speed. AWS may be deliberately throttling the Internet connection to limit the likelihood that people will use it for undesirable things. There's a chance that a home network might be faster, but you're likely to get the fastest connection to NCBI by using an academic system that is linked to NCBI via a research network.
Another possibility is using Aspera for downloads. This is unlikely to help if bandwidth is being throttled, but it might help if there's a bit of congestion through the regular methods:
https://www.ncbi.nlm.nih.gov/public/
NCBI also has an online book about best practises for downloading data from their servers.
On a related note, just in case someone sees this and EBI/ENA is an option, there's a great guide for how to do file transfer using Aspera on the EBI web site:
https://www.ebi.ac.uk/ena/browse/read-download#downloading_files_aspera
Your command should look similar to this on Unix:
ascp -QT -l 300m -i <aspera connect installation directory>/etc/asperaweb_id_dsa.openssh [email protected]:<file or files to download> <download location>
In my case, I've just started downloading some files from a MinION sequencing run. The estimated completion time via standard FTP was 12 hours for about 32GB of data; ascp has reduced that estimated download time to about an hour. Here's the command I used for downloading:
ascp -QT -l 300m -i ~/.aspera/connect/etc/asperaweb_id_dsa.openssh [email protected]:/vol1/ERA932/ERA932268/oxfordnanopore_native/20160804_Mock.tar.gz .