FireFox freezes on occasions for 10-20 seconds.

[GreyGeek]

Dmesg revealed:

[187293.994185] [drm] stuck on render ring
[187293.994246] [drm:i915_set_reset_status] *ERROR* render ring hung inside bo (0xfecb000 ctx 0) at 0xfed0a04

A Google search found:
https://bugs.freedesktop.org/show_bug.cgi?id=75405

There is an easy fix if your Intel graphic chip gives you this problem.
In /etc/X11/ create a file called xorg.conf. If it already exists rename it xorg.conf-yyyymmdd and copy it to xorg.conf, otherwise create a new one. In the new one put:

Section "Device"
Identifier "Intel Graphics"
Driver "intel"
Option "AccelMethod" "uxa"
EndSection

If you already have that section in xorg.conf then modify it to look like this.

What does it do? Kubuntu 14.04 is defaulting to the faster "sna" acceleration method. This reverts it back to the slower but more stable "uxa" method.