Video using CPU, not graphics card
In general, unless you set it up to be otherwise, videos in the web browser don't use the video card at all. This means your CPU is doing all the hard work to decode and display the video. I don't know enough about specs to know whether this would be happening with your processor, but I have an older single-core AMD processor that usually gets maxed out at 100% when watching videos on the web (especially Flash videos). When that happens, the frame rate gets choppy and the browser gets sluggish.
Recommended (non-technical) workarounds
There are fixes for some setups (see below), but in the meantime, you might try some of the following workarounds when you go to watch a movie:
- Decrease the bitrate (or "quality") of the video stream. Yep, that means if your video is set to HD, like 720p or higher, you're going to have to knock it down to a lower quality. I don't like it, either, but it's better than choppiness.
- Reduce the load on your CPU from other tasks. Close unnecessary programs, tabs, etc. that are using processor time. You can see a list of running programs and sort them by their CPU time (
CPU%) in System Monitor. IMPORTANT: Close the programs properly; do not use the System Monitor to end the task!
- Try watching the video in the opposite full-screen mode. If you typically watch videos in full screen, try watching them in the browser window. If you typically watch videos in the browser window, try watching them full screen. I've heard both changes work for people; it depends on your display setup (and I don't know much about how that part works).
- Watch the video in a different format, if possible. This mostly applies to Flash videos. Try using the video hosting site's option for HTML5 video, if available (YouTube is one of the places that allow you to do this). I've also used MiniTube to watch YouTube videos in a non-Flash format (but you have to find the video again through MiniTube—you can't just enter the video's URL).
Developers are working on this problem
None of the above tips are a true fix. However, there is work getting done to solve this problem.
Flash developers have a beta of Flash Player for Linux that uses hardware acceleration (i.e., uses your video card to help out) on some setups. I also know that VDPAU is used to make the graphics card available for this kind of problem (I've used it to solve the same problem on one of my own computers), but it only works on NVIDIA graphics cards (as far as I'm aware, at least). I don't know of anything for ATI graphics cards. Then again, I don't know a lot of what's going on in video and graphics software development for Linux anyway. Someone else may be able to give more detail on this point.