ALMA datasets can be very large, and take many hours to download. However, there are a couple of steps a user can take to minimize the wait:
Ensure you are on a good internet connection. Many commercial home internet providers will allow you to start downloading fast, but then reduce the download rate with time. You are usually best off connected via a hard wire internet connection to an academic network.
The download script functionality automatically downloads the data in up to five parallel streams on Linux and MacOS operating systems.
Also the file-list allows you to download several files in parallel using your own browser-plugin download manager. However, please be gentle on the number of parallel streams you are using.