My desktop (really a netbook) has gigabit ethernet but it's not connected when the slower wireless works just fine. My ADSL is slower still so it just doesn't

My desktop (really a netbook) has gigabit ethernet but it's not connected when the slower wireless works just fine. My ADSL is slower still so it just doesn't matter. So should I swap it for an RPi? For what use is all the processing power I have.