You can run 4 clients on 4 GB ram, a old nvidia GTC 550i and a simple 2.8ghz dual core intel CPU, limit each client to 30 FPS and ur good to go, I can run 10 clients or more on my i7, 64GB ram, and GTX 970's x4, it depends on the build and what your trying to do. If the clients are ment to only gather FPS isnt a huge issue.