After installing 10.10 on an AMD FX 8350, I got to booting it, and first i booted normally with just npci=0x2000, this got it all the way past the loading screen up to the point where I had just a grey screen.
Thus i went and complete the Grafix steps to get that working, now i am unable to get past the loading section with the hackintosh zone logo. Then I used npci=0x2000 -v to see where it was stopping, and here it is
"hfs: mounted Yosemite Zone on device disk3s2"
"hfs: unmount initiated on Yosemite Zone on device disk3s2"
At this point I have no input from my keyboard, but it is still illuminated
AMD FX 8350 (4.0Ghz Stock, Overclocked to 4.5Ghz)
Gigabyte GA-970A-DS3P (AM3+ Socket)
Sapphire R9 270x