Size of a Word and addressing

Question

I was refreshing myself on memory information and I am confused on the size of a Word. From my understanding, a Word is not a universally defined size, but is a size defined by

Answer 1

You are confusing word size and byte size, because word size is determined by the processor and byte size is universal.

Without using PAE (Physical Address Extension) a 32-bit processor can only handle 4GB of RAM since there are only 2 ^ 32 = 4,294,967,296 different numbers that can be represented using 32 bits. This is a hardware limitation.

32-bit systems utilizing PAE can address more than 4GB, by mapping processes to page tables. This grants each process access to 4GB of memory. Via supporting PAE, the 32-bit version of Windows Server 2003 Datacenter supports up to 64 GB of RAM on x86-based computers.

Edit

Word size denotes the amount of bits a CPU can process at one time. So 32 bits = 4 bytes. However, word size and address size are often used interchangeably which leads to confusion, since they are indeed different. The Pentium Pro was a 32-bit CPU with a 36-bit wide address bus, allowing 64GB of accessible memory (via PAE.)