In my PC, I can watch youtube videos without any problem. However, they lag so much on fullscreen, that it's basically impossible to watch them. How can I fix this?

10 Answers 10


You should check your about:gpu section in Chrome/ium. In older PC's HW Acceleration is disabled by default and you only can enable it by overriding the settings in the about:flags.

  • Open the about:flags in your address bar
  • Look for Override software redendering list
  • Click "Enable"
  • Restart Chrome/ium

Had the same problem.

Then I realised Chrome already Flash player built in.

I had also installed the Flash player manually so they were apparently interfering with each other. I just disabled the built in Flash in Chrome and voilla. No lag anymore in full screen.

Hope it helps someone.


This happens to me as well, specially on my older PC, if I watch a youtube video in fullscreen, it lags. What I usually do is to stretch the screen, but not to fullsize or I play it on VLC Player, where it does not lag anymore in full-screen.

To play a Youtube video on VLC Player, copy the address (if you are using secure "https" connection, remove the "s", make sure the link is http://www.youtube.com/watch). Then go to File -> Open Network Stream and paste in the main YouTube URL for a video.

Unfortunatelly this only works with youtube videos for me, Vimeo videos don't play on VLC.


I have solved using youtube HTML5 video player.

You can enable HTML5 video player using the following page: http://www.youtube.com/html5

Now videos are fast and the laf was gone. I have tested it on Chrome.

  • 1
    This is not a solution but a workaround – Joren Sep 22 '13 at 22:44
  • I disagree with Joren -- the questioner asked about YouTube, not Flash. Google has been moving more and more of their videos to be HTML5-player compatible. Also Adobe has dropped linux support for their Flash player, so it has only received security patches for several years now. – Tommy Trussell Feb 3 '15 at 22:26

Tried turning down the resolution on the player? Normally, it will automatically up it when you go to fullscreen.

Other than that non-fix, all I can do is feel with you. If internet is running already, then the drivers are at the best they can be. I've found that Ubuntu is just slower than Windows when it comes to wireless Internet.


Not long time ago there was extension for Firefox named Flash-Aid but it's deleted now. Try to find some similar extension/software.


My cable company (Time Warner Cable in the US) throttles youtube. I blocked the IP addresses associated with the throttling (

iptables -I FORWARD -s -d -j REJECT

with sudo (where is my LAN subnet).

See the (reddit source) in order to find out what IP addresses are doing the throttling.

You can also check your youtube dl speeds with http://youtube.com/my_speed


Today I struggled with the same question, and I managed to fix it. What I did was, I browsed to the file /etc/adobe/mms.cfg (if it doesn't exist, create it) and I added the line OverrideGPUValidation=true to it.

I then restarted my computer and the lag was gone, both on Firefox and Chrome. No 3rd party applications needed.

  • Was your lag in fullscreen mode only? – Sergei Jan 20 '16 at 13:52
  • @Sergei I don't remember. I left Ubuntu for Arch and am now running lag-less. – Jeroen Bollen Jan 20 '16 at 19:16

For me, changing from the AMD fglrx to the xserver-xorg-video-ati driver in driver management helped.

Unfortunately other software doesn't like xserver-xorg so meanwhile I am using rekonq or konqueror which seems not to be lagging.

  • did you try xserver-xorg-video-amdgpu? – Sergei Jan 20 '16 at 13:54

Some people have had success with this:

I thought I'd let Ubuntu use more cache... Try this:

(In the terminal)

sudo gedit /etc/apt/apt.conf.d/70debconf

Then put this code:

APT::Cache-Limit "100000000";

on that file and then save it

Next type this code on your terminal

sudo apt-get clean && sudo apt-get update --fix-missing

and you won’t find apt cache limit again in the next time.

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