Putting it in video game terms, 520 Gb of total traffic / minute is only 18 MB of I/O traffic per frame, or less than one uncompressed 4k video frame.
How inefficient can your backend be to require 16000 vCPUs and 116TB of RAM for *just* 8 million users.
That's 1 vCPU every 500 users and 14GBs per user