AlphaTurlte :
Thank you for your reply!
So it doesn't matter if it is a Mirco ATX? And will that be fine for games like Witcher 3?
Those cheaper boards make a few compromises. You're limited to one graphics card and very few additional expansion slots (for ultra high speed storage, or a sound card, etc). You're also limited to two memory slots, but now 16GB modules are on the market, you can still have up to 32GB which is very unlikely to be an issue for you in the life of the machine. There's fewer SATA ports and the like, but still plenty for almost everyone's needs. The motherboard has no impact on performance, so it'll be just as fast as a super-expensive board. It's just fewer features, which really only matters if you have unusual needs like loads of disk drives, or multi-graphics card options.
It'll run Witcher 3 with your 970 every bit as well as a premium $400 socket 1151 motherboard will with that CPU & GPU.