Let's break it down.
For the purpose of solely gaming (or even for other workloads and applications) you should be investing into at least a B350 Motherboard so that you have the option of overclocking your CPU if and when you feel like it (investing into better cooling than the stock option if wanting to achieve higher overclocks)
Make sure your RAM is 2x8Gb so that you get dual channel performance.
Not sure what power supply you have in mind but hopefully it's a quality made one and not a stinker.
The SSD you've chosen is way over priced for your needs. Seeing as how you went with a 250GB I am to assume you are not using it for storing the games but just for other smaller programs, applications, and small files along with the OS, and since you say this system is for gaming only, you have no need for the insane performance capabilities of the 970 Evo. Go for a Crucial MX500 250GB. It will perform fantastically and cost way less.
Had to google what the hell Korpusas was, apparently the MasterBox 5 Case I am assuming. That's fine.
You're good on the 3TB HDD for storage, although, I would opt for the Seagate Barracuda line instead of Toshiba.
You have a GTX 1070 in there, not sure which one but overall it should do you wonders at anywhere from High - Max presets at 1080p depending on the game giving you 60 or more fps, but only if you overclock it to get the bump in performance, at stock settings it'll get you there but not as easily as an overclock will.
Overall aside from the few changes I've suggested, your build is perfect.