I opened a bug report her: https://bugs.freedesktop.org/show_bug.cgi?id=89291
-The problem affects only ivybridge. -The problem is gone after activating sna acceleration. With -intel-2.21.15 from testing I recognized other bugs (e.g. big shadows under the nautilus window). -With -intel-2.99.917 from experimental only activating TearFree (perhaps i915.semaphore) results in smooth animations. I think it's not a major but annoying bug. All machines with ivybridge are infected. There isn't a solution with the actual driver in stable, testing or sid. The only workaround is fiddling around with experimental and some modifications in /xorg.conf.d.
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