[bdog@bdog ~]$ beryl --replace&
[1] 15948
[bdog@bdog ~]$ sh: xvinfo: command not found
sh: xdpyinfo: command not found
**************************************************************
* Beryl system compatiblity check                            *
**************************************************************
sh: xvinfo: command not found

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                    : failed

No sync extension
beryl: No sync extension