In the page you linked to, it mentions that Mathis formula does not apply if packet loss is low. In that case, you want the formula above: throughput <= RWIN / RTT. If your window is large enough, then round trip time isn't a big deal (unless you have a really big connection)
RTT is a large factor in throughput at the beginning of the connection, when tcp slow start is restricting the opening of the receive window.
RTT is a large factor in throughput at the beginning of the connection, when tcp slow start is restricting the opening of the receive window.