Gpu output through mobo hdmi

If you have z68 with lucid virtu then yes but will have a small performance decrease, and maybe a few rare bugs. You could get a dvi>hdmi adapter if you don't need sound.

I don't recommend you to do so, even you can.

What you can do is get an adapter, and if you need the sound just go from the sound card or motherboard. HDMI Sound are sometimes buggy.

I wouldn't say hdmi sound is buggy, people just tend not to put the right settings.