32 bit processeor have 4GB address space. 2 pow 32 = 4 GB (4294967296)
Is that mean 64 bit can access can access 2 pow 64 = 16 exabytes ??
1. 64 bit does not mean all the bits of those points are actually used.
x86_64 -> 48 bit address lines. -> theoreitically 256 terabytes of RAM.
2. mother board have their own limits how much RAM can be supported.
Physically we can only have few slots ;)
3. OS may have internal limitation on how much it can support.
Linux allows 128 TB of virtual address space per process on x86_64.