Hi,some comments on your Video Card Drivers taken from your info : u'Acceleration blocked by platform', {u'status': u'unavailable', u'description': u'OpenGL Compositing', u'log': [{u'status': u'unavailable', u'message': u'Hardware compositing is disabled', Firefox is Multi-Processor and Multi-Thread so your seeing Sandbox, Firefox, Add-ons/Extensions/Video + '''''To be Checked and turned off unless needed for accessibility : ''''' Please : go to the Firefox 3 Bar Menu --> Options --> Privacy & Security panel and under Permissions check (put a tick in the box) the setting to Prevent Accessibility Services from accessing your browser. '''''Multi-Processor Support : ''''' Go to the 3 Bar Menu then Options --> General --> Performance and untick everything. change the recommended size lower then see how it runs. Note: 1 = No Multiprocessor = slow again. Try 2 Restart Firefox after making these changes please. Note : Hardware Acceleration is for Video Card, Monitor to see if remain off or to turn back on. Only Disable as last resort. '''''Multi-processor Can completely disable it this way in about:config :''''' dom.ipc.processCount set to 1 browser.tabs.remote.autostart = false browser.tabs.remote.autostart.2 = false *http://kb.mozillazine.org/About:config Only move to esr if low ram and old system. '''''Firefox Extended Release Version :''''' Firefox ESR does not come with the latest features but it has the latest security and stability fixes. *https://support.mozilla.org/en-US/kb/switch-to-firefox-extended-support-release-esr If do please : *https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles *https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer