So I am making a mobile game with multiplayer elements in it, an I have a few questions from the fantastic UE4 community. I am planning on having a rack of 42 1u servers, and I want to build them, what parts would I need to focus on, the CPU or the video card, if a video card is even needed. I have much knowledge in PC building. All help is appreciated, thanks in advance. 
- Why 42 servers?
- what makes you think you even need servers.
- What is your game…?
- Whats your budget
- I’m pretty sure you posted in the wrong area.
For security you will come out cheaper purchasing a server. To use your own cpu will breed many hackers plus 24/7 debugging when a simple price can spring u world wide at the fraction of the cost if you built your own servers. Not cheap at all. Look into server there are many types. Good luck