The same here,
The good neighbor policy on the DIR_655 is very bad for me, maybe nice for the neighbors.
Before i have a DIR-635 with 10/100 lan the wireless working very fast.
Now with the DIR-655 it is very bad 65 mbps i have a internet connection 120 mbit and the fastest i get wireless is around 60 mbit.
My old router i'm getting around 80~90 mbit it's the max for the wan side. So it was a lot faster. Thank you d-link!!!
I going to use my old one and trow this one away if there is no solution for the slow wireless. 
Hi Vespa,
You are not going to be getting 300 Mbps connection if viewed from the Router, if not a D-link Wireless Adapter that works with the DIR-655 Router.
With that said, these are the settings for the D-Link DIR-655 Wireless Tab.
Choose your 802.11 Mode, that includes 802.11n.
Uncheck Enable Auto Channel Scan.
Pick Wireless Channel 11. (For me, that produces the highest speed.)
Transmission Rate: Best (automatic)
Channel Width: Auto 20/40 Mhz
Security Mode: WPA-Personal
WPA Mode: WPA2 Only
Cipher Type : AES
Group Key Update Interval : 3600 seconds