While browsing to sites which require Flash I sometimes experience a freeze of the screen (probably because Flash uses hardware acceleration). When I switch to some virtual terminal and back to the one where Xorg is running, it sometimes works again, but often there are glitches then.
I have an Intel Ivybridge i7-3632QM with HD 4000 Graphics.
Some other people over at https://bugs.archlinux.org/task/39250 are affected too.

dmesg gives the following:
[ 6355.622355] perf samples too long (2614 > 2500), lowering kernel.perf_event_max_sample_rate to 50100
[ 6552.198078] [drm] stuck on render ring
[ 6552.198080] [drm] GPU crash dump saved to /sys/class/drm/card0/error
[ 6552.198080] [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
[ 6552.198080] [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
[ 6552.198080] [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
[ 6552.198081] [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
[ 6552.222326] [drm:i915_set_reset_status] *ERROR* render ring hung inside bo (0x2e35000 ctx 0) at 0x2e36a04
[ 6564.246267] type=1006 audit(1394731871.071:4): pid=458 uid=0 old auid=4294967295 new auid=1000 old ses=4294967295 new ses=3 res=1