Remember that "flags" are experimental by nature. Opera may eventually make this feature a standard, non-optional setting. Until then, this verified tweak gives you a competitive edge in download speed—without installing any third-party extensions or software.
To enable the Parallel Downloading flag in Opera, follow these steps to increase your file download speeds by allowing the browser to establish multiple connections for a single file. How to Enable Parallel Downloading Access the Flags Page : Open your Opera browser and type opera://flags into the address bar, then press Search for the Flag opera flags enableparalleldownloading verified