I have a 50MBit/s internet link and am connecting via WiFi (802.11n). However, when I run a speedtest, I get a max of ~35Mbit/s. If I then plug in via ethernet, I get the full 50MBit/s.
My signal strength is >90% and is connected at 150MBit/s.

So I should be able to get all 50MBps, rather than 35.
I am the only user connected (at the time of testing), my encryption is set to Mixed(WPA+WPA2)/PSK.
Any ideas?