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**srochford** The change from 8 to 16 etc wasn't just about memory. Remember, there are two important sets of "numbers" in a CPU - the width of the address bus (controls the maximum RAM you can address) and the width of the data bus (controls the size of numbers you can process).

On 8 bit CPUs you were stuck with numbers no bigger than 2^8 (256 decimal). This meant that to do maths with "real" numbers meant lots of complex fiddling around (eg the Z80 CPU allowed you to use pairs of registers so you could deal with numbers up to 2^16 but that still doesn't allow you to handle decimal numbers with any precision)

Anything involving real maths needs more bits (eg true colour graphics need 24 bit numbers for each pixel). If you want to be able to process graphics reasonably quickly, you want to be able to do more than 1 pixel at a time.