This is likely fixed in xenial then which has a later snapshot. If you want something backported to 15.10 then feel free to bisect but until then this stays closed
** Changed in: xserver-xorg-video-intel (Ubuntu) Status: New => Fix Released -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-intel in Ubuntu. https://bugs.launchpad.net/bugs/1525207 Title: xserver-xorg-video-intel slow perfomance, needs updating To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1525207/+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