Got my ESXi build done...
I couldn't get it to POST, and had to do some troubleshooting. So disconnected all drives except 1 SSD. Used different USB drives etc etc... then realized that ASUS are assholes and don't follow convention.
Yes, I had overlooked the fact that the white fan header, is actually the CPU fan header, LOL
I had assumed the white one was the fan-opt - yes I don't read manuals after building them for around 25-30 years now
Anyway, all up and running now. Just sorting ESXi itself out now, got it installed, changed to a static IP, but then wouldn't connect to webgui... so changed back to DHCP, and not giving me an address now. So got some figuring out to do.