Hello, It's been awhile since I posted.
On my Mac Pro 3,1 2008 Rig, I recently purchased an Original Nvidia GTX GeForce Titan 6GB. (I sold of my more expensive Titan X Maxwell) This Titan is a Kepler one. So I was hoping it would work out of the box with Mojave and High Sierra and it does for the later.
With High Sierra 10.13.6, it will use Apple's drivers natively. It also works with Nvidia's web drivers. This is nice especially if High Sierra does another update, I won't have to wait a day. It supports metal,
"feature set macOS GPUFamily1 v3." For Mojave, I hope v4 is not required or Family2 v1. On HS it fully supports 4K. The Titan has two DVI-D ports, one Display Port and One HDMI Port. It works just like my Titan X did with Nvidia's drivers.
This card is unflashed and is an original PC Card. I don't plan on getting it flashed. I am not too keen on some of the mis-information about speed and flashing cards because an unflashed card with the right drivers seems to run the exact same an a card flashed for EFI and boot screen. It also has no barring on 4K and scaled res'. You just don't get the boot screen and boot options.
With Mojave, my original Titan behaves a bit differently. I'm able to switch screen resolutions, but does not get the full range of scales resolutions. Video acceleration and Metal is NOT on. The Apple Geforce drivers don't load. It loads the Nvidia startup. K100Hal and one other Nvidia driver but the GeForce ones do not.
Without the GeForce kext's loaded the UI on Mojave actually looks quite good. No transparency but it works and does not have any artifacts. Things just run slow at time because there is no GPU acceleration at all (currently).
I hope Apple does not expect the cards for Mojave to flashed or be only a certain card and official Mac cards because for along time now since Lion I believe we've been able to use PC Cards without an issue.
For a boot screen, I keep my GeForce 8800 GT Card installed and I've used the IDE DVD drive's power for one of my eight pin connector on the Titan. And I then have two dedicated six pin connectors for the Titan and the 8800GT. This a lot cheaper than flashing a card or selling off my 8800GT and card and send out my Titan to MacVidCards to be flashed. He's charging $160. So buying the extra wiring to use the IDE power costs roughly 15 dollars. And I can still run Snow Leopard on my old card and my 8800GT runs fine on a x4 port. I keep it there because it is not needed that often. I have a 1TB PCI SSD on the x16 slot 2 and my Titan is on x16 slot 1. Overall it displaces the heat pretty well staggering the cards. On top of all that I am not swapping out cards to either. Both cards remain installed and are fully functional.
I am sure Nvidia's web drivers will solve my issue. It just would have been nice not to have to wait for Apple to release the GM.
My Titan card was just $250 on eBay. It looks brand new. Whoever sold it either took really go care of it or did a really good job refurbishing it. The fan had zero dust on it and the clear window was had no dust inside either.
For High Sierra, I highly recommend the original Titan or Titan Black card. The ability for these Kepler cards to work out of the box is just awesome. The whole Titan line is stout. I am not sure on the 1060-1080 cards as I hear mostly that the 1080 Ti requires more power for the 2008, so I've been sticking with the Titan line. The original Titan and Titan Black actually use less power than the Titan X and Titan Xp. They are way cheaper too. It's just not certain if the Titan which was made around 2013 will fit the bill for Mojave.