Had the same problem on teh 3.4 mini I use with an old nVidia 4 mx 4000 card, so here's the solution:
1. install sabayon in graphical mode
2. once it finishes and reboots set accel-manager on AIGLX
3. if the drivers get you into trouble install the drivers from the nVidia website yourself.
4. generate an xorg.conf from the nvidia-settings and make sure you have the following 2 option lines to xorg.conf in Section "Device" and you'll get your window title bars.
Option "AddARGBVisuals" "True"
Option "AddARGBGLXVisuals" "True"