Solid 48 frames in Chrome for me - the awkward thing is that I'm running an Alienware laptop, and regardless of value for the money, Alienware doesn't skimp on power; so 48 FPS on effectively Flappy Birds is worrying when it runs Crysis at a steady 35.
I'll have a look at your cap later, though from debugger figures you've posted I can't see how it could get faster