Understanding the number of bits in gaming consoles


Possible Duplicate:
What does 8-bit / 16-bit actually refer to?

Some of the consoles I've owned are:

  • 8 bit NES
  • 16 bit Megadrive (Genesis)
  • 64 bit Nintendo 64

I've always been curious about what the number of bits specified actually means? I realise that when taking unsigned integers into account, the maximum value 8 bits is 255, 16 bits is 65,535, and 64 bits is9,223,372,036,854,775,807.

Does it refer to the amount of graphical data that can be transfered at any one time? Or the colour palette? Or the largest a numeric data-type can be? Or some other factors?

Best Answer

It generally represents the size of the CPU registers and the main memory bandwidth. This equates to data processing abilities and is most commonly associated with the amount of memory that is addressable (see 32-bits and the 4GB memory limit). Registers can easily be combined to work with extra large numbers, and is not necessarily related to the graphics link or graphics memory bandwidth.