DOMANDA Chi mi aiuta a capire questo problema

[geniosparsux]

The second issue isn't a fault of ASUS, rather an issue with the Wi-Fi alliance 20/40MHz Coexistence mechanism. If any 802.11g or 20MHz-only device is on the WAN, the maximum rate is reduced to 130Mbps in the 2.4GHz band. This is an issue many people might not know about and why you might read many complaints as to why the 5GHz SSID cannot be seen, or the speeds are reduced even with a 2x2 300Mbps connection. Unless you are running off of a pure 11n 5GHz 40MHz network, expect lower speeds than maximum.

Non è una questione di inglese che so abbastanza bene, ma tecnica. Chi per cortesia mi spiega in cosa consiste questo fantomatico secondo problema che ho trovato in questa recensione delll Asus RT-N56U? E' grave?
Grazie