How much NSX consume physical resources on a single host?
There is no correct answer for this query . We all know that in general ,server virtualization has got more benefits and all the pillars(Network,Storage,Server) which makes a true SDDC platform benefit from this. So a SDN platform like NSX gets direct benefit of all vSphere features. So one shouldn't be worried about single host resource consumption . Practically, server sizing and vSphere design is equally important for optimal performance while implementing NSX and that is key success criteria as per my experience. Get that foundation right and the solution will work flawlessly. In addition to this monitoring solutions like VROPS&Network insight will be a perfect fit to understand the resource consumption once the solution is implemented with actual workload placement. Please do refer some of the articles for a better understanding on design best practices and performance tunings that might be required based on the design.
https://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/whitepaper/products/nsx/vmware-nsx-brownfield-design-a… \\https://cms.vmworldonline.com/event_data/5/session_notes/NET1343BU.pdf
Please do revert if you need any additional details.
Best of luck with exam preparation