Just wondering thoughts on on board graphics? Mainly if I plan on definitely running a separate graphics card do I need on board graphics or is there any benefit to having it(or even a disadvantage)?
If you will have a dGPU then, there's no need of having a iGPU.
I would say, the benefit from having a iGPU is you could install the OS or turn on the PC without a dGPU, but you still could turn on the PC but it would not display anything, but that isn't anything too bad since it's rare for people to do that.
Resuming, If you have a working dGPU and a CPU without iGPU there's no problem since you have the dGPU to plug the monitor and use the PC.
dGPU: Discrente GPU.
iGPU: Integrated GPU.