When a person downloads a file from a website in Google Chrome, a request is sent from the device to a server where the files are located. Once the connection is established, the server starts to transfer that data to their device to be accessed whenever the user wants.
Parallel downloading enables a single device to maintain multiple connections to the server, which downloads different files from the host server simultaneously. The ability to establish these different connections theoretically means that downloads could take much less time than they would at the rate of a single connection.
Download speed, still, of course, hinges on internet speeds — which can be tested on a variety of sites. If your ISP and internet speed are the bottleneck of your download, parallel downloading may have no effect at all.
Similarly, if the file is hosted on a website that limits simultaneous server connections — which may be the case for large file-hosting websites — then parallel downloading will not circumvent this. The same can be said if the same host server has an unusually high load or is experiencing technical problems.
