Safest OSX to upgrade to with a GTX 680? & Using Native OSX driver vs NVIDA driver?

Hi everybody,

I’m about to update my 5.1 Mac (2012) OSX from Yosemite but seems like there are no drivers for Mojave (long thread about this!). I also read that there are CPU slowdowns with High Sierra, so I’m a bit confused:

-Have these High Sierra slowdowns been fixed?

-With using the native OSX drivers in Mojave work ok?

Thanks for the help!