I have a 
DIR-825 with a WUSB600N linksys usb ( wireless adaptor )
the maximum speed of the adapter I can get is no more then 150Mbits/s..... 
I use the WAP2 AES on both 2.4 and 5G network
the signal is at 52% on the router page 
when I use different software ( 3 different ) they say all the same connect at 95% 
I'm at 15' no wall between adapter and router so I believe more the 90-95% signal 
one of my friend have dir-628 with the same adapter and get between 270-300 
any ideal on which setting or configuration I can play with ?
thank you