The new Nvidia drivers that come in the utilities folders are for quadro cards only. There are no drivers for the GTX users that will drive 8.5 properly. I had artifacts and playback problems that did not go away until I reinstalled 8.3 on my machine where I have the driver that works with avid.
My conclusion is that if you have an NVIDIA GTX card you will have to wait to install 8.5.
I noticed that 8.5 did not appear as an update in the application manager for me. It is clear to me that it is known that it will not run. I have seen no mention of this anywhere from AVID.
If I am wrong about any of this please point that out, I would love to use some of the features in 8.5.