The 802.11ac 5GHz protocol delivers 433 to 6933 Mbit/s, and the 802.11n protocol between 72 to 600 Mbit/s. In principle, this should be the same performance. But according to a performance benchmark of the magpi magazine , the Raspberry Pi 4 can provide up 58/114 Mbps, while the Raspberry Pi 3 is at 59/97.67 Mbps.