"Dual-Channel Architecture" is a physical property of the motherboard, not the memory.
A normal Single-Channel motherboard has one 64-bit memory controller and thus one 64-bit interface. Each module of DDR also has a 64-bit interface (unless it's ECC then you get an extra 8 bits = 72-bit). This single controller accesses memory modules in all of the DIMM slots.
A Dual-Channel motherboard has two 64-bit memory controllers and thus one 128-bit interface. Often you'll see something advertising 128-bit memory, etc. This is the basis since Dual-Channel uses the same 64-bit DDR memory.
However, in Dual-Channel boards, the first memory controller only accesses modules from the first two DIMM slots. The second controller accesses modules from the 3rd (and 4th in the case of some boards) so you have two controllers simultaneously accessing memory.
Theoretically, this doubles the speed at which all memory related functions can occur. In real life, it's not doubled because of physical restrictions and other interactions, but it usually does give a nice boost in memory performance (much more on Intel boards than AMD due to advanced buffering techniques).
You may have noticed that neither controller accesses memory from the other's respective DIMM slots. This means you must use at least two modules of memory in order to run a Dual-Channel setup. One module for each controller to access. If you only run one module, even in a Dual-Channel capable motherboard, you'll run it as if it were a Single-Channel motherboard since only one of the controllers has access to it.
The underlying idea is that when one controller is working the other is resetting or preparing to access/write memory and vice-versa so it reduces memory, "down time."
The biggest requirement is that the modules you use are closely enough matched that they can run almost exactly the same. They will run with the same latency setting
