Thanks for the clarification. The situation you described could well be associated with the gpu lockup. The way to be certain is to look at dmesg after experiencing one of these lags:
[ 630.190999] [drm] capturing error event; look for more information in /debug/dri/0/i915_error_state [ 630.192053] i915: render error detected, EIR: 0x00000010 [ 630.192053] i915: IPEIR: 0x00000000 [ 630.192053] i915: IPEHR: 0x01000000 [ 630.192053] i915: INSTDONE_0: 0xfffffffe [ 630.192053] i915: INSTDONE_1: 0xffffffff [ 630.192053] i915: INSTDONE_2: 0x00000000 [ 630.192053] i915: INSTDONE_3: 0x00000000 [ 630.192053] i915: INSTPS: 0x0001e000 [ 630.192053] i915: ACTHD: 0x052175d0 [ 630.192053] i915: page table error [ 630.192053] i915: PGTBL_ER: 0x00000001 [ 630.192053] [drm:i915_report_and_clear_eir] *ERROR* EIR stuck: 0x00000010, masking That one looks like it happened about 10 minutes after booting. ** Changed in: xserver-xorg-video-intel (Ubuntu) Status: Incomplete => Triaged ** Changed in: xserver-xorg-video-intel (Ubuntu) Importance: Undecided => High ** Summary changed: - [gm45] GPU lockup EIR: 0x00000010 PGTBL_ER: 0x00000001 IPEHR: 0x02000000 + [gm45] GPU lockup EIR: 0x00000010 PGTBL_ER: 0x00000001 IPEHR: 0x02000000 - sluggish behavior with gimp and totem -- 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/1116732 Title: [gm45] GPU lockup EIR: 0x00000010 PGTBL_ER: 0x00000001 IPEHR: 0x02000000 - sluggish behavior with gimp and totem To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1116732/+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