there's no games using dx11.2 afaik, and even then the changes over dx11 are just internal, nothing the OP would actually see.
unless idk, he cares about having his shaders precompiled.
also, talking of w8 gaming
http://www.eightforums.com/general-support/34689-windows-8-8-1-mouse-lag-microsoft-adressing.html
i tried w8, launched my fav game, was horrified, launched all my other games, and promptly formatted and installed W7.
an OS that doesnt have a raw input is not something i'd call a "gamer" OS.
@ Rick
the 970 isa great card, but so is the 770. mine (at 1080) doesn't make a sound, runs cool, and you could buy one for £130 on eBay. six months old card, mind you. should the OP get the 970 and throw it away in six months? for future proofing?