If you are in the habit of opening large number of tabs in the background, and doesn’t want to hurt the current page you are loading, then here is a nice addon for firefox which will load the tabs one by one making sure that the internet connection is not being flooded and thereby allowing you to browse new pages without any halts while the background tabs are being loaded.
This addon is very useful for people who are having slow internet speeds. As the name suggests Load Tabs Progressively addon will load the background tabs one after the other and you can browse without any problems.
You will have the option to set the maximum number of tabs to be loaded concurrently, maximum number of unread loaded tabs, next tab to reload etc.
You can set the value maximum number of concurrent loading tabs according to the speed of your connection and based on your current requirement. If you are downloading any other files then you could give a small value in there and if your internet connection has more speed then setting the value higher wont be a problem.