~$ beryl --replace
**************************************************************
* Beryl system compatibility check *
**************************************************************
Detected xserver : NVIDIA
Checking Display :0.0 ...
Checking for XComposite extension : passed (v0.3)
Checking for XDamage extension : passed
Checking for RandR extension : passed
Checking for XSync extension : passed
Checking Screen 0 ...
Checking for GLX_SGIX_fbconfig : passed
Checking for GLX_EXT_texture_from_pixmap : passed
Checking for non power of two texture support : passed
Checking maximum texture size : passed (4096x4096)
[Warning ]: Relaunching beryl with __GL_YIELD="NOTHING"
**************************************************************
* Beryl system compatibility check *
**************************************************************
Detected xserver : NVIDIA
Checking Display :0.0 ...
Checking for XComposite extension : passed (v0.3)
Checking for XDamage extension : passed
Checking for RandR extension : passed
Checking for XSync extension : passed
Checking Screen 0 ...
Checking for GLX_SGIX_fbconfig : passed
Checking for GLX_EXT_texture_from_pixmap : passed
Checking for non power of two texture support : passed
Checking maximum texture size : passed (4096x4096)
beryl: Another window manager is already running on screen: 0
beryl: No manageable screens found on display :0.0