3 ms·

Why there is no a 256 bit Microprocessor or a 512 bit Microprocessor?

• lutusp 14y ago
  Think about what you're asking. It's a simple matter of practicality and economics. If a communications channel is long, the number of parallel bits must go down. Wireless, for example -- technically, it's a communications channel one bit wide. We used eight-bit pathways when that made economic sense, then we moved to 16-bit and 32-bit. Another issue is the distinction between data word size and address bus size, which operate by different rules and priorities. If memory size becomes large, eventually the address bus must become wider to accommodate this. I can remember a spell in the development of x86 processors when memory banks had to be switched in and out of the address space to get around the limitations of an address bus that was too narrow. But in the final analysis, it's a simple issue of performance and economics. If a certain performance level can be achieved with a given word size and address bus width, by tuning our designs we eventually reach a point of diminishing returns -- where increasing word size or address bus width costs more than the return in performance.