With headers, 940 mbps is about the maximum for gigabit Ethernet: https://www.smallnetbuilder.com/lanwan/lanwan-howto/33095-ho....

And of course, Google Fiber like AT&T is an oversubscribed consumer level connection. Each use shares a 2.4 gigabit up/1.2 gigabit down GPON with some number (typically 16) other users.