in this build i used intel cpu and nvidia gpu as you see
i5 9600k doesnt fall far from the i7 and the i9 with minor diffrence of around 5-10% in gaming performace depands on wich game(mostly wil be a 3-10 fps change) but cost around half of those cpus price
1660ti gives a great performance for its low price,its compete with 1070 and in some games its even close to the 1070 ti
the pc is well cooled by 6 fans(4 of them are beasts with insane amount of airflow)
there is an evo860 ssd for fast pc boot and shorten loading times
2x8GB ram for dual channel performance-high speed ram 3000mhz to ensure cpu best performance
so at most games this system wil go around 80-120+fps depand on which game you play
hope this build helped you
CPU
Intel - Core i5-9600K 3.7 GHz 6-Core Processor
$264.89 
CPU Cooler
Dynatron - K199 14.72 CFM CPU Cooler
$34.85 
Motherboard
Gigabyte - Z390 UD ATX LGA1151 Motherboard
$115.99
Memory
G.Skill - Aegis 16 GB (2 x 8 GB) DDR4-3000 Memory
$77.99 
Storage
Samsung - 860 Evo 250 GB 2.5" Solid State Drive
Seagate - Constellation ES 3 TB 3.5" 7200RPM Internal Hard Drive
$57.40 
$54.99 
Video Card
Gigabyte - GeForce GTX 1660 Ti 6 GB AORUS Video Card
$309.99 
case
Corsair - SPEC-05 ATX Mid Tower Case
$49.98
psu
EVGA - BR 450 W 80+ Bronze Certified ATX Power Supply
$34.89 
case fan
Delta Electronics - FFB1212EH-F00 150.33 CFM 120mm Fan
$23.10 
Delta Electronics - FFB1212EH-F00 150.33 CFM 120mm Fan
Delta Electronics - FFB1212EH-F00 150.33 CFM 120mm Fan
Delta Electronics - FFB1212EH-F00 150.33 CFM 120mm Fan
$23.10
$23.10
$23.10
Total: $1090.35