Same problem with Xubuntu 14.04.3. I switched back to the xserver-xorg- video-ati driver to see if it fixes the problem.
This was while I was still using fglrx: $ ps aux | grep /usr/bin/X root 1470 0.7 24.3 4415808 1973744 tty7 Ss+ Sep04 65:07 /usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch $ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 14.04.3 LTS Release: 14.04 Codename: trusty $ uname -a Linux bmaupi-xubuntu 3.16.0-48-generic #64~14.04.1-Ubuntu SMP Thu Aug 20 23:03:57 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux $ uptime 09:41:21 up 5 days, 16:04, 8 users, load average: 0.45, 0.67, 0.71 $ dpkg -s fglrx Package: fglrx Status: install ok installed Priority: extra Section: restricted/misc Installed-Size: 163590 Maintainer: Ubuntu Core Developers <ubuntu-devel-disc...@lists.ubuntu.com> Architecture: amd64 Source: fglrx-installer Version: 2:15.200-0ubuntu0.5 $ fglrxinfo display: :0.0 screen: 0 OpenGL vendor string: Advanced Micro Devices, Inc. OpenGL renderer string: AMD Radeon(TM) HD8490 OpenGL version string: 4.4.13374 Compatibility Profile Context 13.35.1005 -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to fglrx-installer in Ubuntu. https://bugs.launchpad.net/bugs/1354350 Title: Xorg memory leak on 14.04 To manage notifications about this bug go to: https://bugs.launchpad.net/fglrx/+bug/1354350/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp