How to Increase the Number of Simultaneous Download Limit in Firefox
To Increase simultaneous download limit:
1. In the browser address bar, type about:config and hit enter.Click the I’ll be careful, I promise! button
2. In the Filter field, Search for network.http.max-persistent-connections-per-server
3. Double click on network.http.max-persistent-connections-per-server… and enter the amount of simultaneous downloads you’d like from the server