You don't need two PC's to stream to be a successful streamer, but it does have 2 big advantages:
For gaming, gommru uses a Intel Core i7-7700K CPU with a GIGABYTE AORUS GeForce GTX 1080 Ti GPU. He uses a ASUS ROG Strix Z270-F motherboard. gommru uses G.SKILL Trident Z RGB Series 16GB memory.
For streaming, gommru uses a AMD Ryzen Threadripper 1950X CPU with a EVGA GeForce GTX 1050 Ti SC GPU. He uses a ASUS Prime X399-A motherboard. gommru uses CORSAIR Vengeance LPX 16GB memory.