The difference between 32-bit and 64-bit.
In: Technology
Here’s an explanation which doesn’t use any strange analogies:
The number refers to how many bits there are in special storage locations called registers, which is where the CPU stores the data it’s working on right at this instant. As other posters have said, more bits means you can store bigger numbers in those registers, but being able to do arithmetic very, very quickly on 64-bit numbers instead of 32-bit numbers isn’t why computer makers made the jump. The reason is because CPUs use the data in registers to get data out of memory, so the bigger your registers are, the more memory your system can use.
How much memory are we talking about here? Well, 32-bit numbers top out at 4 GB of RAM. You can only uniquely number something above four billion different objects if you only have 32 bits to work with. Four billion may sound like a lot, but 4 GB is kind of a constraining amount of RAM, even on desktops, these days. With 64 bits, you can uniquely number over [18 quintillion](https://en.wikipedia.org/wiki/9,223,372,036,854,775,807)* different objects, so that’s the limit of 64-bit addressing. We likely won’t hit that for a while yet.
*(I linked to the right thing. Read the article for the *unsigned* value, and realize that x86-64 isn’t the whole world.)
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