A lot of people have been wondering if Hackintosh works on the X99 Platform. I have successfully setup Yosemite on my GA-X99-UD4 build with dual GTX 970s - both being recognized - along with a 5820k, SSD, 16GB DDR4 of RAM and more. What's working: Full CPU performance (no power step though), Ethernet, both GTX 970s are recognized with full hardware acceleration (and CUDA support on both GPUs), App store/iMessages etc, all USB ports, all connected storage devices (3 SSDs, 2 hard drives.) What's not working: onboard audio (can be fixed, but I use cinema display's audio) The build: Intel Core i7 6-Core 5820k w/Hyperthreading @ 4.3ghz (Haswell-E) Corsair H110 Cooler Crucial MX100 256GB SSD (Yosemite drive) Corsair Air 540 Case 2x GTX 970 Gigabyte WindForce Cards GIGABYTE GA-X99-UD4 Motherboard 16GB Crucial DDR4 RAM Installation: Follow this video tutorial: [video=youtube;cx_RD7CduDM]https://www.youtube.com/watch?v=cx_RD7CduDM[/video] To install OS X, you just need the very basis of OS X to install. To boot the installation drive, I had to use npci=0x2000 nv_disable=1 -f -x -v ^ there may be more, I forgot, but I am certain of those. To boot OS X after installing, you want to follow the youtube tutorial exactly. That includes copying over the modified kernel before booting OS X. To boot OS X, you need to use npci=0x2000, nv_disable=1, -f -v. Install NVIDIA web drivers from here. You can then reboot with npci=0x2000 nvda_drv=1 -f. From here, use Multibeast to install the kexts for your hardware. Most everything works out of the box. Don't go crazy on the kexts. A DSDT is not required - sleep even works without it. Everyone's system is different. But you will need NVIDIA's web drivers if you have a GTX 970, 980 or 780 Ti. Pictures: Yosemite specs: Both GPUs are recognized: All 12 threads are put to use: The Machine, "Hackbox Pro" It's cool in here! I love my pixels! (taken in windows) This thing knows no lag, everything is instant and smooth. Yosemite is a bit of a RAM hog, using 7GB RAM just with 4 tabs open in safari and iTunes. I'd suggest 16GB for extra caching and more speed. Yosemite really uses the extra RAM, unlike Windows. Notes: -Update the BIOS on this motherboard ASAP...Mine came with the first version, extremely buggy. Latest version has no issues to report. -You can install NVIDIA CUDA drivers. Applications that take advantage of CUDA cores can take advantage of both GPUs for maximum performance...And it flies! -The 5820k hits about 50C on average under 100% stress...At 4.3ghz. I should be able to get at least 4.5ghz, but do not care at the time. -I always recommend having separate drives for OS X and Windows. I bought two SSDs - one specifically for OS X, one specifically for Windows. Crucial is a great brand. I will help anyone who needs it if your specs are similar to mine. Post below!