Confirmed, we just did a 4930K build with the Titan X, took a few trials and errors to get it to work since I couldn't boot up the computer with the OS X build in Nvidia driver....so finally figured out to add:
nv_disable=1
After that, got the machine to boot, and then it was just a matter of installing the latest Nvidia web driver and insert the boot load command to use the web driver instead of the OS X one.
Hopefully when 10.10.3 comes out the Titan X will work right out of the box.
Either way, I can confirm that the card does indeed work just fine.