Are you on Linux? Because it is disabled by default on linux and you will need to force it on if that's the case
On windows it should be enabled by default in your browser when you update your graphics drivers, I would try that first if you havnt' already
You can see if it's enabled in your browser's settings but that depends on what browser you are using
In Firefox it is under performance>general and unchecking the use recommended performance settings
On chrome you go to settings>advanced>system and make sure it is enabled
You can also try forcing it on which again depends on the browser
In chrome type "chrome://flags/" (minus quotes) in the search bar and enable override software rendering list, then click relaunch
On firefox you have to type "about:config" (minus quotes) and then type layers.acceleration.force-enabled and enable it there