Wireless Performance to ReadyNAS - at my wits' end...

Update: Changed my router to an Asus RT-N66U running DD-WRT. All else configured as above.

Wired speed was already close to the gigabit Ethernet limit with the old router, and is basically unchanged with this one:

NAS performance tester 1.4 http://www.808.dk/?nastester
Running warmup...
Running a 400MB file write on drive W: 5 times...
Iteration 1:     111.11 MB/sec
Iteration 2:     111.42 MB/sec
Iteration 3:     97.32 MB/sec
Iteration 4:     110.50 MB/sec
Iteration 5:     89.89 MB/sec
------------------------------
Average (W):     104.05 MB/sec
------------------------------
Achievement unlocked: 100MB+/sec write speed!
Running a 400MB file read on drive W: 5 times...
Iteration 1:     113.64 MB/sec
Iteration 2:     110.50 MB/sec
Iteration 3:     114.29 MB/sec
Iteration 4:     112.04 MB/sec
Iteration 5:     108.40 MB/sec
------------------------------
Average (R):     111.77 MB/sec
------------------------------
Achievement unlocked: 100MB+/sec read speed!

Wireless speed (5.2GHz 802.11n, as before) is better with this router:

NAS performance tester 1.4 http://www.808.dk/?nastester
Running warmup...
Running a 400MB file write on drive W: 5 times...
Iteration 1:     20.82 MB/sec
Iteration 2:     21.22 MB/sec
Iteration 3:     21.94 MB/sec
Iteration 4:     22.06 MB/sec
Iteration 5:     19.11 MB/sec
------------------------------
Average (W):     21.03 MB/sec
------------------------------
Running a 400MB file read on drive W: 5 times...
Iteration 1:     13.67 MB/sec
Iteration 2:     12.45 MB/sec
Iteration 3:     13.81 MB/sec
Iteration 4:     13.61 MB/sec
Iteration 5:     13.59 MB/sec
------------------------------
Average (R):     13.43 MB/sec
------------------------------