Individual sticks of memory always are powers of 2 because of how multiplexers/demultiplexers work. Basically there is a bit of circuit where every word of mem

Individual sticks of memory always are powers of 2 because of how multiplexers/demultiplexers work. Basically there is a bit of circuit where every word of memory connects to a bus. The Mux decides which one of the words is loaded on the bus. A series of wires controls which gate is open. If there is 1 wire there are two possibilities 0, 1 If there are 2 wires there are four possibilities 00, 01, 10, 11 If there are n wires there are n^2 possibilities. Not using all the possible words for the number of wires. Example 3 words when using 2 wires would cause there to be inputs that break the state machine the instruction stack is interacting with and make developing for the chip very complicated. So the number of words that can be pulled is restricted by the capacity of the Mux, which is driven by wires that are either off or on. This causes the powers of 2. http://en.wikipedia.org/wiki/Memory_controller http://en.wikipedia.org/wiki/Memory_controller http://en.wikipedia.org/wiki/Multiplexer http://en.wikipedia.org/wiki/Multiplexer