[SOLUTION] Slow framerate with fglrx

If you run glxinfo and get something around 60FPS (300 in 5 seconds), then you have the vertical sync set to QUALITY.

Open the AMD control center with amdcccle
Go to the «More Settings» item inside the «3D» Page on the left. Change «Wait for vertical refresh» to «Performance».

Done.

I get this:

[email protected]:~$ fgl_glxgears
Using GLX_SGIX_pbuffer
10617 frames in 5.0 seconds = 2123.400 FPS
10988 frames in 5.0 seconds = 2197.600 FPS
10852 frames in 5.0 seconds = 2170.400 FPS