PC3-14400 / 8 = 1800 (This is the chip type, AKA DDR3-1800).
1800 / 2 = 900MHz (This is the bus clockspeed).
900 / 4 = 225MHz (This is the memory clock).

DDR2 bandwidth was (MEM MHZ) * 2 * 8.
DDR3 bandwidth is (MEM MHZ) * 4 * 8.

And this is the primary benefit of DDR3, it has 4 cycles per clock instead of 2 cycles with DDR2.