Rt-n66u, d-link dns-343

[mmmmmm]

Hello,

I am running some LAN speed test on my home network.
I have a feeling that I am missing some settings to get the right speed so I am asking for your help.

The setup is shown in the image below.

Asus RT-N66U with the following FW and settings:

D-Link DNS-343 network attached storage with the settings below:

 

[mmmmmm]

Test 1: Wired notebook "Realtek RTL8168D/8111D Family PCI-E Gigabit Ethernet NIC (NDIS 6.20)" to RT-N66U to D-LINK DNS-343

Test 2: Wifi "Intel(R) WiFi Link 5300 AGN" - 2.4Ghz to RT-N66U to wired D-LINK DNS-343

Test 3: Wifi "Intel(R) WiFi Link 5300 AGN" - 5Ghz to RT-N66U to wired D-LINK DNS-343

My feeling is that these values are not so good and I am trying to find out the weak link in my setup.
I was expecting to get the same speed (at least 20MB/s) on both cable and wifi, but as you can see it is not the case. Wifi speed is half the wired speed.

Should I configure the network adapters in 1000 fill duplex?

To make matters worse, when I am downloading torrents over the Wifi the speeds drops even more.
The same torrent file that I am able to download to tha NAS over the wire at 8MB/s (my ISP limit), when using wireless (to the NAS) I get about 3-4MB/s with many fluctuations.

Am I missing something here?

Please advice.