The 2.4 GHz band can technically support speeds of up to 1.2 Gbps on Wi-Fi 6 routers when paired with a fast enough Internet plan. But in practical situations, most people using the 2.4 GHz band likely have Wi-Fi 4 or 802.11n routers, as Wi-Fi 5 only supports the faster 5 GHz band. In these situations, the 2.4 GHz band's theoretical maximum is around 300 Mbps. But with other factors like interference from other devices and the crowding from other networks on the 2.4 GHz band, actual speeds get decreased even further. In general, you can expect less than half of your plan's rated speed on the 2.4 Ghz band. Try band steering to get the most out of your 2.4 GHz and 5 GHz bands.