Problem. The Firefox browser does not use the hardware root of my video card (Radeon HD 5550 video card). Online video is very slow on some sites (everything is fine on YouTube). There are also artifacts in the form of a flickering horizontal stripe on the second monitor when duplicating the screen (this stripe is very annoying). In the Chrome browser everything works fine after forcibly enabling hardware acceleration (in the Chrome browser I enabled the “Override software rendering list” parameter by changing the switch to the “Enabled” position) in the Firefox browser I changed the “layers.acceleration.force-enabled” parameters from “false” " to "true", but that didn't help. Operating system Windows 10 with the latest updates, Firefox browser 123.0.1 (64-bit), latest video card drivers for Windows 10 amd catalyst 15.201.2401-151104a-296388c-ATI

Online video is very slow on some sites (everything is fine on YouTube).

Install the Media Feature Pack if applicable.

Go to about:support in the address bar and check the "Codec Support Information" table.

Try changing media.hardware-video-decoding.force-enabled to true in about:config then restart the browser.

There are also artifacts in the form of a flickering horizontal stripe on the second monitor when duplicating the screen

Try changing gfx.webrender.compositor to false then restart the browser.