GTX 1070 TI in a 950€ Gaming PC?

cheater7694

Prominent
Dec 3, 2017
2
0
510
Hey Guys.
I'm going to build a Gaming PC for Christmas.
Atm those are my specs:

Mainboard: ASRock Z370 Pro4
Graphics: Palit GTX 1070 TI Dual
CPU: i5-8400 6x2.80GHz
RAM: Crucial Ballistix Sport LT 16GB
Case: Sharkoon VG4-W red
Power Adapter: Something with 400W, my dad will buy it for me so I dont havé to struggle with that
Hard disk: Same as above

Now my questions to you:
1. Will a i3-8100 also work with such a good GPU or will it have worse performance than the i5?
2. Maybe the GPU from another Manufacturer? Or even a GTX 1070 OC or sth like that which is performing better than the TI and is cheaper?

I'm thankful for every answer :)