My 6235 worked fine for a few months and now I noticed that it will not connect at any speed fasted than 54Mbits (based on Windows 7 Network status report). Both 2.4 and 5.2 bands and both on Windows 7 and Windows 8 get the same results. I have another computer that does 802.11n fine and channel bonding with my router so the router settings and securty settings are not the cause! It did work fine a couple of monts ago, I remember is showing upper 200's Mbits.
I changed every setting on the advanced tab and no change. Uninstalled and reinstalled drivers. Reinstalled Windows 7. I even placed in another computer and it did the same thing only 54Mbits.