https://bugs.freedesktop.org/show_bug.cgi?id=69723
--- Comment #79 from Martin Andersson g02maran@gmail.com --- Maybe we don't have the same issue then (or our cards have different sensitivity to this issue) because I see a huge improvement with spread spectrum disabled. I saw that you had got hangs while playing serious sam 3, so I bought it and tried with spread spectrum enabled and it hung within 5 minutes, but when I disabled spread spectrum I played for 2 hours without problems.
I will continue testing it and report back if I encounter any problems.