I just built a pc nearly identical to yours, i7-4770, same exact ram, gtx 760 sc acx, etc.
I am using Windows 8.1. Though Win 8.1 is stupid on many points, e.g. the pointless departure from UI standards that required no revision, it seems to be working very well for gaming. I have been playing BF4 at 60 fps on all max settings...and it stays at 60 no matter how busy the action is.
It is hard for me to say, since I do not perform any serious benchmarking experiments, but I see a difference with the Directx change in Win 8.
Also, there is a comment above about the motherboard...I went with the Asus Hero 6 and it is completely awesome and very easy to manage. The software and features are on par with boards another tier or two above the Hero's price range.
Here is my build:
http://pcpartpicker.com/user/aogiss/saved/3qh2
I only have on GPU, despite what the list states. Since I had one already, I added another to the list to ensure I bought a big enough PSU, in case I went SLI, which I probably will not.
Also, the cooler in my build is great. I cranked the CPU up to 4.4 and I have never seen a temp higher than 37C. It is huge, but fit with no problems that case.