Hi, I can't confirm if this the case with the RE200 but many older or cheaper extenders have an Ethernet port that only handles traffic up to 100Mbs. The newer/better ones have Gigabit ports (like my RE650). In AP mode there should not be any significant signal loss from the router to the AP. High speed mode is a feature that only applies if you are in Extender mode, when you only use one band to communicate with the router (such as the 5G) and broadcast the other band (2.4G) in order to get full-duplex instead of half.