The memory seems high actually, I've seen other C / C++ / Go implementation using less than a 1GB for 1m connections. Pretty cool nonetheless!
https://github.com/uNetworking/uWebSockets
https://speakerdeck.com/eranyanay/going-infinite-handling-1m...
https://github.com/uNetworking/uWebSockets
https://speakerdeck.com/eranyanay/going-infinite-handling-1m...