Windows 10 Pro – how to install nvidia drivers manually

Okay, that's not windows update that you get. Thats an ITB (In the box ) driver that's getting loaded. It comes as a feature with Windows 8 onwards. Regarding disabling it, Not sure. But you could try custom installation of an updated driver version(just driver package and not additional components). ITB should not load of the installed version is an updated version

Unfortunately, what you wish seems impossible unless you have some guru-level programming and OS knowledge. The GTX 970 driver only supports back to the 400 series. Basically nVidia would have to make a conscious effort to merge support of the 200 series into the current driver. I would imagine it would also increase the driver size to over 600 MB. Good luck in your quest but overall I too think that the PhysX delivered by the 280 will actually hold back your 970

There was a video I saw of a GTX 580 using a 8600 GTS for PhysX and the FPS drop was substantial vs. just running everything on the 580. I cannot find it though :(

^ I found the video! https://www.youtube.com/watch?v=cbww3dhzK0M the details

Here is a solid run-down: http://www.volnapc.com/all-posts/how-much-difference-does-a-dedicated-physx-card-make and this picture specifically http://www.volnapc.com/uploads/3/0/9/1/30918989/7654086_orig.jpg. Unfortunately the blog does mention using a 200 series with 900 series so I question the credibility.