Ah, ok. It makes sense now, each of the sticks are 400mhz, but they combine bandwidth.
Nooooo...
MHz means how many clock cycles, in terms of millions of clock cycles per second. So 400Mhz is 400 Mllion On/Off cycles per second. On every clock cycle you have whats called a rising and a falling edge. Rising is during switch on, and falling is during switch off.
Normal non-ddr ram can only transmit dad on the rising edge, but DDR ram can transmit data on both the rising AND falling edges. It effectively doubles the speed. Dual channel means your two ram sticks are in parallel. So each one of your "800 Mhz" sticks is actually running at 400. In dual channel mode you effectively have a single "1600 Mhz" ram stick, or actually for a combine 800Mhz
Think of those push button grill ignitors, or those large push button lighter. Those are like Non-DDR ram, they only spark when you push the button down. If it were a "DDR" lighter, it would spark again when you let go of the button. You are still doing the samething as before, but you able to now get two sparks out of it. In dual channel you would have two grill lighters. Now a "Dual Channel DDR" grill lighter now lets you get 4 sparks per each press and release
