Broadcasting the desktop to a streaming service requires capturing the desktop, converting the video and transmitting it over the Internet.

Suggested codec: H.264

1. Don't spend too much on hardware (try low-end)
2. 720p@30fps
3. Render, convert and broadcast on a single device
4. (1080p@60fps in the long run)

• Test H.264 configurations
• Look one that's fast on the CPU
  • Some programs may support GPU
• In a second step mind the network usage

• FFmpeg wiki: Encode H.264
• Calculating CPU usage of a process in Linux