https://bugs.freedesktop.org/show_bug.cgi?id=52345
--- Comment #1 from Matt Turner mattst88@gmail.com 2012-07-21 16:43:06 UTC --- (In reply to comment #0)
glxgears gives 60 FPS in both cases, which leads me to beleive that power management does work.
Does your glxgears print this?
Running synchronized to the vertical refresh. The framerate should be approximately the same as the monitor refresh rate.