I did some extensive reading on this motherboard, and nowhere have I found the actual video system used... they kind of imply that onboard support is implemented in the chipset, but that doesn't really sound right.
It does appear to have some rather high end features that look interesting (like Thunderbolt support and the UEFI flashing at hardware level), but I haven't seen anything indicating its actual video subsystem. All that's ever said is "intel HD video".
Hmm... here's the actual ASUS download page:http://support.asus.com/download.aspx?SLanguage=en&p=1&m=P8Z77-M&hashedid=7yxGrS52FngihsKT
From here you can get the motherboard manual. Some stuff looks interesting under the "System Agent Configuration" section as described on page 2-21 of the manual, but I can't copy it and paste it here from Acrobat Reader.
It still doesn't say what actual driver is used, but has some options for hardware setup that might impact operation...
ASUS does not rate this board for use with Linux. As such, I'm a little disappointed with them on this.