Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Download speed with firefox is less than 50% on modem connection speed, other browsers do not have this problem, and it gets worse the longer firefox runs.

  • 2 replies
  • 11 have this problem
  • 1 view
  • Last reply by CEPhill

more options

this question is on the forum, but all the tech answers refer to downloading firefox, except on that has only two answers. The Firefox browsers runs at full download speed of my connection until I open a window, then the dowload speed drops very quickly to 50% or less of the available speed, even if only one window is open. I've run the speed test on firefox and IE with both windows open, IE is at full speed while FF is hitting 20% if lucky. This did not happen in previous versions prior to updating the firefox.

this question is on the forum, but all the tech answers refer to downloading firefox, except on that has only two answers. The Firefox browsers runs at full download speed of my connection until I open a window, then the dowload speed drops very quickly to 50% or less of the available speed, even if only one window is open. I've run the speed test on firefox and IE with both windows open, IE is at full speed while FF is hitting 20% if lucky. This did not happen in previous versions prior to updating the firefox.

All Replies (2)

more options

How are you determining this download speed?

Most speed test websites use the flash plugin to measure the speed, so if you encounter problems that there might be a problem with the Flash plugin or the plugin-container process.

Did you check your security software and made sure that Firefox and the plugin-container process have full permission to access internet?


You can create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem

more options

These have all been done. The problem occurrs immediatly, and is obvious on sites other than the speed test site. I made the speed test the homepage, and tested immediatly upon starting. the download speed was in the appropriate range. An IMMEDIATE retest on the site, without starting any other tabs or windows, was at 50% speed and dropping, and never again reached full speed. Repeated process with IE, no problems, full download speed available.