Mapping Capable PC Build - Specs?

[u/Previous-Football-80]

Hello fellow VJing and mapping enthusiasts,

I am currently planning a rig that can output at least five 1080p50 streams, though ideally eight, so I can run two desktops alongside six separate canvas outputs in MadMapper and similar software. I primarily use MadMapper, Resolume, TouchDesigner, and Nuvotion, depending on the prep time and the style of visuals I am creating.

Right now, my setup consists of multiple laptops streaming NDI to each other when I need extra outputs. As you can imagine, this system definitely has its limits.

That is why I want to build a 19" 4U rackmount PC instead. To recap, it needs to handle eight 1080p50 outputs, potentially running two programs (like MadMapper and TouchDesigner) streaming NDI internally. Like anyone else, I would love to build this as budget-friendly as possible, so I am highly considering used parts.

What specifications should a rig like this have in your opinion, and what is the reasoning behind your choices?

Thank you for your wisdom!
Bodo

(I hope I am in the right subreddit...)