I use open source driver for AMD HD6320 video card. I followed the instruction in this article Force Enable Hardware Acceleration in Firefox but if I try to play HD video in firefox it's very slow. How can I be sure that hardware acceleration is used? Thanks.
Check out (type as url):
This should give you info on supported features (like hardware rendering)
You can try to disable/uncheck hardware acceleration in Firefox. It may feel counter intuitive but has often worked for me. You can find it here:
Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"
Another good thing to try is to install Chrome (or Chromium) and check that browser has the same problem. From experience I have had lagging in Firefox but Chrome worked fine.
If you do want to install the ati binary drivers you can go to
Ubunti Settings > Software & Updates > Tab: Additional drivers