The text anti-aliasing in Firefox works best with hardware acceleration enabled. If you check the support information page, you can see whether Firefox currently is using hardware acceleration. You can open that using either: * "3-bar" menu button > "?" button > Troubleshooting Information * (menu bar) Help > Troubleshooting Information * type or paste about:support in the address bar and press Enter Scroll down to the Graphics header, and then in the table that follows, there is a line showing the number of accelerated windows out of the total number of open windows ("GPU Accelerated Windows"). Does that indicate that Firefox is accelerating all windows? If hardware acceleration is not happening, that could be for any of these reasons: (1) Firefox needs you to update your graphics card/chipset driver software. See: [[Upgrade your graphics drivers to use hardware acceleration and WebGL]]. (2) Even though you have the latest driver software, there is a known problem, so it is temporarily blocked in this version of Firefox. (3) You turned off hardware acceleration, perhaps for troubleshooting. Does any of that seem to apply to your Firefox?