I recently purchased the Z97-HD3 rev 2.0 F6 bios motherboard and found it a challenge to get working right, certainly far more difficult than Z87 or Z77 motherboards. I am using 8gb of GSkill RAM(F3-12800CL9D-8GBRL), very popular choice, Mavericks 10.9.5, an i5-4460 Haswell processor and an EVGA GT 610 video card(01G-P3-2615-KR), an inexpensive card with an HDMI, VGA and DVI ports. Never been fond of Intel HD anything on board graphics which always seem to be a pain to get working right, particularly when it comes to getting audio through the on-board HDMI port.
Two major problems came up immediately - intermittent kernel panics and no audio hardware detected in the Audio pref panel, even though MultiBeast has drivers for the "current" and "legacy" Realtek ALC887 hardware used on this board.
Random kernel panics: this seems to be a widespread problem on many Intel Series 9 motherboards. Judging by all the posts, the problem seems to be RAM related. I even got kernel panics while using a UniBeast installer. Changing the RAM merely altered the pattern of when the kernel panics would take place. In the past I have always set the RAM to Profile 1 in the bios in order to get the motherboard to recognize and run the RAM at 1600mhz. The panics stopped completely when I reset the RAM to its default setting, which for this rev 2.0 F6 Z97 board fortunately is 1600mhz instead of 1333 mhz, the usual default for older boards. I think this is some sort of a Gigabyte problem, since they have changed the initial bios setup with some sort of fancy preference choices for RAM performance to make it more appealing to newcomers, but not a very helpful addition to setting up the motherboard for Mac OS.
No Audio hardware detected: This was the hardest problem to solve. Tried a variety of ALC887 MultiBeast drivers. None worked. Chose the Intel Series 9 option, of course, and experimented with the 01-03 options which were added to the boot.plist in the Extra folder. Even tried the "Universal" (VoodooHDA) options in MultiBeast, only one of which seemed to do something. However, the audio in this one sort-of working option was loaded with hiss in one channel and basically unusable. Studied Toleda's lengthy and complicated post on this subject but couldn't easily find an answer in this arena. What I think was going on was that the combination of these new Haswell "refreshed" processors and what might have been a Realtec ALC887 variant chip on this motherboard not covered by the MultiBeast provided options was to blame(my 887 device was a 80868CA0). Almost gave up on this one when I stumbled across a new VoodooHDA option - Voodoo_HDA_2.8.5_MAV.pkg.zip - which is written for use with Mavericks. Worked perfectly. It even produced two HDMI options in the Output section of the Sound Pref. panel, the second of which piped audio into my GT 610 video card. Not sure if the first HDMI option does the same for the HD-4600 ports on the motherboard, none of which I tested or used. No need for the HDMIAudio-1.0.kext extension to rout audio to most nVidia cards that come with HDMI ports.
Solving these two major problems makes this Gigabyte ATX Z97 HD3 motherboard now work perfectly. I deleted the generate C and P states options in the Boot.plist since apparently they are no longer necessary. Geekbench scores were unchanged at around 11,300. Amazingly enough, sleep works perfectly too. But it was a bit of an adventure getting to this point but in the end well worth it, since the HD3 motherboard is quite inexpensive. Hope this lengthy post helps other Intel Series 9 Z97 motherboard users.