You don't need two PC's to stream to be a successful streamer, but it does have 2 big advantages:
Derrick 'Reaver' Nowicki is an American player who previously played for Cloud9. He is currently a full-time Twitch streamer.
For gaming, Reaver uses a Intel Core i7-8700K CPU with a EVGA GeForce RTX 2080 Ti GPU. He uses a GIGABYTE Z370 Aorus Gaming 5 motherboard. Reaver uses CORSAIR Vengeance LED 16GB memory.