Figure 3 is a shot of the 6504n's main board. The CPU is a Ralink RT1310, with 16 MB of RAM and 4 MB of flash. The 10/100 switch is a Realtek RTL8305SC, which handles both LAN and WAN port. It's too bad that Edimax opted for 10/100 Ethernet instead of gigabit, but I guess they wanted to save their pennies.
Figure 3: Main board
The radio is integrated into the main board and uses the Ralink RT2860 Baseband / MAC and RT2820 2T3R Tranceiver.
Edimax sent an EW-7718Un nMax Wireless 802.11n USB Adapter along for testing, since their notebook (Cardbus) card wasn't Wi-Fi 802.11n Draft 2.0 certified. Figure 4 shows a composite photo taken from the FCC ID docs of the top and bottom of the board.
Figure 4: USB adapter board
This time, it's a Ralink RT2870 Baseband/MAC that is paired with the RT2820 transceiver. As near as I can tell, there are only two antennas in this adapter.