32 bit vs. 64 bit architecture

32bit means that cpu register has 4byte size and the cpu bus can deliver up to 4bytes at once. 64 bit means 8bytes.

 

This bus delivering unit is very important because it means memory capacity. In case of 32 bit cpu, bus unit size is 32 bit. It means 4 bytes. And 4bytes can express 4giga bits addresses. You know? Each address cell size is one byte based on byte addressing standard. So, 32bit architecture supports 4giga bytes memory capacity.

 

Don't be confused. In 64bit architecture, you can use just one giga byte ram. Operating system will use extended virtual memory through memory swapping. But if you have larger memory size ram, the swapping cost will be reduced.

 

So, in 32 or 64 bit architecture, the important is CPU register and its bus size because it can express memory addresses.