You don't need two PC's to stream to be a successful streamer, but it does have 2 big advantages:
Teodore better known online as Teo, is a streamer and content creator from Sweden. He has over 1.4 million followers on YouTube.
For gaming, Teo uses a Intel Core i9-9900k CPU with a Palit GeForce RTX 3080 GPU. He uses a ASUS Z170 Pro Gaming motherboard. Teo uses Corsair Vengeance RGB 32GB memory and a Samsung 850 EVO 500GB SSD for storage.
For streaming, Teo uses a AMD Ryzen 7 1700X CPU with a MSI GeForce GT 730 GPU. He uses a Gigabyte GA-AB350M-Gaming 3 motherboard. Teo uses Corsair Vengeance RGB 16GB memory and a Samsung 850 EVO 250GB SSD for storage.