ASUS does not cut corners when it comes to component selection. The RT-N56U is powered by a Ralink SoC RT3662F which contains both CPU running at 500MHz and 2T3R dual-band 802.11n radio transceivers. It also has a Realtek RTL8367M Gigabit Ethernet switch controller which supports 9k jumbo frames, 8MB flash and 128MB RAM. With more memory, the router can have a larger NAT table which could hold up to 300,000 data sessions.
The four small chips at the bottom right are the radio power amplifiers. Three U.FL connectors on the far right added the possibility of attaching external antennas. There are five internal antennas altogether: three on the top PCB and two on the bottom.
According to ASUS, three of the antennas for the 5GHz band with 5.1dBi gain and the remaining two are for the 2.4GHz band with 3.8dBi gain.