Ops, It's with with 2.10 i obtain ~700FPS, i mistyped, sorry.

  I tried to change vblank_mode with driconf and with set param 
vblank_mode, but i obtain the same fps with 2.11 and 2.12 drivers:
> 311 frames in 5.0 seconds = 62.175 FPS

With 2.12 glxgears rates ~700FPS.