Jwk sorry I don't have any experience with the Gigabyte motherboard world but for sure your 1080TI graphics card would work. Is that card installed in your 1st PCIE motherboard slot? It should be ensure a stable Graphics intergration on a Hackintosh. If not, I'd recommend you back up your system with Carbon Cloner so you can easily go back to what you have (make sure you copy your existing EFI driveinto that installer manually) and re-build Os High Sierra with the 1080TI in 1st PCIE slot and maybe forget the other Saphire card. Get your USB OS High Sierra 10.13.6 Installer to boot wth the bootflag nv_disable=1 (which you can set in your Clover config file when you prepare your USB Clover bootloader. This will disable the Nvidia card's settings then when you confirm you have 10.13.6 installed with that card accepted, then you can go and try my install process from my previous post.
The Gigabyte Z97X-UD5H-BK is a pretty easy mobo to work with, and the Gigabyte BIOS are some of the most compatible for use with OSX. The second slot is the 'first slot' in this case because the first slot is 'x1', the second is 'x16'. Yeah, I haven't gotten to the 'brew.sh' part in my research yet, and I'm a bit surprised to hear you bring this up, because I think I read every post in this thread, and you're the only one that brought that ane webdriver.sh up, although I think I saw it mentioned on vulgo's github notes; I've also been looking at Benjamin Dobell's version and don't think I saw it mentioned their. Several people in this thread mentioned having 17G66 and using 387.10.10.10.40.135 (at least one, jonidontcry, using Dobell's script), KhelgeBZW said to add Security Update 2019-007 to 17G66 to bring it up to 17G10021 an use 387.10.10.10.0.133, and I can't find the post right now, but someone mentioned having problems with 387.10.10.10.25.156 but that 387.10.10.10.25.157 worked with full acceleration. Also a number of people mentioned they kept trying update using vulgo's script, and had issues with the driver, even though it looked like it installed without error, and when they disabled SIP and tried to install again, it worked fine. My brain feels like swiss cheese right now.
The drive I'm working on is a clone of my original installation drive, which is still in it's virgin state. I cloned it with Super Duper, which unfortunately doesn't clone the EFI or the Recovery Partition, not too concerned about the former, but the later may be needed to disable SIP; I do have 3 Acronis licenses which I recently bought on sale because it can clone all partitions, albeit only using a Windows pc.
The point of using Brew.sh in terminal is that it bypasses How your High Sierra programming is going to accept compatible Web Drivers. It's really annoying that there is an official Webdriver for 10.13.6 (17G65) but not for our version of 10.13.6 (17G66) so using Brew.sh you can tell the Hackintosh to accept another Wedriver which is close enough, using Webdriver.sh which connects to a current list of webrivers and then selects and installs the one you want manually. In my last post you will see that the Webdriver I chose was released around the time of 10.13.6 (17G66) and I can confirm it's working for me with three monitors without problem. (but no 4k screen size or NVidia Control Panel). Should be able to download CUDA also but I haven't bothered as I use Metal for Video Editing / Colour Grading. Also it's important to make sure you have the right kexts in your Bootloader's EFI before you attempt to install your Webdriver. Also need to inject the right Graphics in your Clover Bootloader's Config file, as I shared in previous post. There's heaps of info online for getting up to speed on setting up your Clover Bootloader.
As mentioned, I'm not up to speed on Brew.sh or webdriver.sh, and this is my first build with Clover, never used WhateverGreen, or Lilu, and Clover Configurator so I've got a lot on my plate right now. I have found the Nvidia webpage of CUDA drivers, in in the notes it mentions that in Windows you right-click on the desktop and it brings up the Control Panel, but on Macs you have to go through System Preferences => Displays to change settings (that on the most recent version of CUDA, the only one I looked at) which may be why you don't see it in the later web drivers as well, anymore. No 4K... hmmm. That's a problem for me, hope I can figure that out. Maybe a custom EDID or a newer driver? I'll have to check my Pulse card; when I tested the HDMI output on it, the only resolution it offered in settings was 1080... I ignored that, because I had it plugged into an Aux input on the front of my AV receiver which I know is only 2k (all the rest of the inputs are 4k); I'll have to swap inputs and see if it will put out 4k).
This may be obvious but when you work with Clover its essentail that you have a 2nd internal clone HD of your entire system using something like Carboncopycloner with it's own Bootable Clover EFI and you update it before you experiment with any new changes and make sure you can comfortably boot that 2nd Drive using Clover as a force Boot from Bios. This way you can always go back and repair your system's EFI partition config file or add or replace kexts as needed or in the worst case, re-install os High Sierra. It makes the whole process less risky and stress free.
Cheers
I have 2 identical workstations with GA-Z97X-UD5H-BK's in them, so one has the master virgin copy, and the other has the working copy and a third drive will have the currently working updates installed on it, so I shouldn't get backed into a corner and have to start from scratch. The cases are Fractals that have slide-in sleds, so easy to swap drives around without any need for tools.
Thanks for the tips, once I digest some of this I may have a few more questions if you're up for it.