Minimum requirements and consumption levels

[Xumeiquer]

Hi, in the very first line of the README.md we can read: [...] Haraka can serve thousands of concurrent connections and deliver thousands of messages per second. Haraka and plugins are written in asynchronous JS and are very fast.

I would like to know what requirements are needed to achieve such numbers. Does Haraka consume more RAM or CPU? Perhaps, for receiving and processing, let's say, 1 million emails what requirements will be needed?

Thanks.