Very slow graphics performance after upgrade 12.04 => 14.04

Solution 1:

The root of the problem described above is probably a lightdm bug:

https://bugs.launchpad.net/ubuntu/+source/unity-greeter/+bug/1292467.

I had this problem on an Atom Mini-ITX motherboard with Intel NM10 graphics which includes an internal LVDS display port. The Boot with "video=LVDS-1:d" workaround solved it for me. Instructions for making the boot option permanent are at How do I add a kernel boot parameter?.

The post by Andy Whitcroft on 2014-04-17 indicates that a fix has been released but it apparently hasn't made it into the updates repository at the time of this writing.

Solution 2:

i faced the same problem. ubuntu was death slow after dist upgrade.

changing to gnome metacity was not an option for me.

what helped in my case:

sudo apt-add-repository ppa:xorg-edgers/ppa
sudo apt-get update
sudo apt-get install nvidia-current nvidia-settings

go to 'additional drivers' and choose any other driver than the selected default one. (was 'nouveau xorg server..' i believe.

(i have a nvidia nvs 310 graphic card and a high res dell display link display)