Have you enabled [http://www.trishtech.com/2013/12/enable-multi-process-tabs-in-firefox/ multi-process]? Additionally, you might tweak the value for '''browser.sessionstore.interval''' parameter in your browser. Enter ''about:config'' in the address bar and click'' I'll be careful, I promise!'' when a warning about your warranty pops up. Then enter '''browser.sessionstore.interval''' in the search bar. Double-click the parameter and change its default value (in milliseconds) from 1500 to a higher value. This should allow Firefox to setup higher time interval for the browser to save a snapshot, so that it will use less RAM memory and videos will be played smoothly. Let me know if you still have issues after performing these changes. ------------------------------ '''If none of these steps help, consider refreshing Firefox based on the below instructions:''' The Refresh feature (called "Reset" in older Firefox versions) can fix many issues by restoring Firefox to its factory default state while saving your bookmarks, history, passwords, cookies, and other essential information. '''''Note:''' When you use this feature, you will lose any extensions, toolbar customizations, and some preferences.'' See the [[Refresh Firefox - reset add-ons and settings]] article for more information. To Refresh Firefox: # Open the Troubleshooting Information page using one of these methods: #*Click the menu button [[Image:New Fx Menu]], click help [[Image:Help-29]] and select ''Troubleshooting Information''. A new tab containing your troubleshooting information should open. #*If you're unable to access the Help menu, type '''about:support''' in your address bar to bring up the Troubleshooting Information page. #At the top right corner of the page, you should see a button that says "Refresh Firefox" ("Reset Firefox" in older Firefox versions). Click on it. #Firefox will close. After the refresh process is completed, Firefox will show a window with the information that is imported. #Click Finish and Firefox will reopen. Did this fix the problem? Please report back to us! Thank you.