Why some people think that 64-bit architectures are no better than 32-bit architectures unless the computer has more than 4 GB RAM? What is so particular about 4 GB?
Why some people think that 64-bit architectures are no better than 32-bit architectures unless
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It’s because they don’t understand the other advantages of x86 64-bit operating systems such as effectively unlimited virtual memory and additional general-purpose registers.
The reason 4GB is a “magic number” is that without PAE, 32-bit x86 operating systems can’t address more than 4GB of physical memory. Even with PAE, processes running on 32-bit x86 operating systems can’t address more than 4GB of virtual memory at a time (and typically only 2GB or 3GB) which is more of a problem if you have that much physical memory.
Also, under comparable conditions, a 64-bit operating system running 64-bit applications will need more memory than a 32-bit operating system running 32-bit applications. With 2GB or less, this can be a significant disadvantage of 64-bit operating systems. With 3GB-4GB, it can cancel out the advantages of a 64-bit OS.