Web pages and videos lag. Especailly Facebook

If you open the same page in Private Window, is there any difference? What is your antivirus/phishing/malware software or security solution provider (do you use anything like AVG or Norton?), and what happens if you disable it (or its "safe browsing" features)? Some maintenance steps to see if any of that changes the results: # Remove some older caches by [[How to clear the Firefox cache|clearing Firefox cache]]. # If it does not help, try [[Clear cookies and site data in Firefox|clearing cookies and data]] for the website you experience troubles with (''warning: you will be logged out on this website''). # If it also does not help, try [[Diagnose Firefox issues using Troubleshoot Mode|running Firefox in Troubleshoot Mode]]. If the problem doesn't persist, please follow the steps from [[Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems | this article]] to troubleshoot further. # If nothing from the above helps, try [[Manage Firefox profiles|creating a new Firefox profile]] and check if the issue persists there. If it doesn't, you can [[Restore bookmarks, passwords and data from an old Firefox profile|start copying files from your old profile to the new one]] to identify which one causes the issue. See [[About your important data and their files|this article]] on what files to copy.