When they say "scanning the whole Internet in 45 min" they mean scanning only one port of every IP address (for example sending a short GET request to port 80/tcp) over a Gigabit link:
2^32 (IP addresses) * 1 (port per IP) * 80 (bytes per packet) * 8 (bits per byte) / 1e9 (throughput in bit/sec) / 60 (sec per min) = 46 minutes (note: excluding multicast space, RFC 1918 space, etc, scanning time would be reduced down to ~35 min)
That's equivalent to "scanning all 65,535 ports of a /16 subnet in 45 min" which does sound less impressive...
2^32 (IP addresses) * 1 (port per IP) * 80 (bytes per packet) * 8 (bits per byte) / 1e9 (throughput in bit/sec) / 60 (sec per min) = 46 minutes (note: excluding multicast space, RFC 1918 space, etc, scanning time would be reduced down to ~35 min)
That's equivalent to "scanning all 65,535 ports of a /16 subnet in 45 min" which does sound less impressive...