What’s the difference between the two?

Key Takeaways

  • Choosing a processor? Consider clock speeds for gaming and energy-efficient designs for work laptops.
  • Bit size in processors determine register width. 32-bit CPUs cap at 4GB memory, while 64-bit go to 18.4 million TB.
  • 64-bit CPUs dominate modern systems. 128-bit not mainstream due to no need for massive RAM amounts yet.

With AMD and Intel adding new and improved features to each CPU generation, there’s a lot to consider when picking out a new processor. For instance, hardcore gamers should focus more on powerful CPUs with ultra-fast clock speeds and sky-high TDPs. But if you want a portable laptop for work, it’s better to pick one with an energy-efficient processor that can provide a longer battery backup.

Up until a few years ago, you also had the option to pick between 32 and 64-bit processors. While 32-bit CPUs aren’t as widely used in mainstream laptops and PCs, x86 chips still power many servers and hobbyist projects. Today, we’ll talk about the differences between 32-bit and 64-bit chips and why the latter is a major step up in terms of performance.

What is “bit size” in processor architecture?

A rendered image of a processor chip on a motherboard, with the word AI on it.

Before proceeding further, it’s time to discuss what bit size refers to when used in the context of CPU architecture. Simply put, a processor’s register width dictates how much data your CPU can handle in a single operation. This relates to how much memory your processor can address. You can calculate the exact amount of addressable memory using the formula 2^n, where n is the bit size of the processor.

As such, a 1-bit CPU could only address 2^1 or 2 unique memory locations. Going up the bit size table, the number of instructions increases exponentially: A 32-bit CPU can address up to 2^32 or 4.2 billion memory locations. That’s a big number, though not quite as large as the 18,446,744,073,709,551,616 addressable memory space of a 64-bit CPU! This number, in turn, influences the maximum memory limit of your system.


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Memory limit and register count

4GB vs 18.4 million TB

G.Skill Trident Z5 Neo RGB atop one another

One of the biggest limitations of older “lower bit” systems was the limited amount of memory they could address. Memory addressing is a technique used by CPUs to store and later retrieve information from the RAM. Without getting into page file and segmentation shenanigans, a 32-bit processor can address up to 4GB of memory. This is because the registers inside an x86 CPU can only hold a maximum of 32 bits, which caps the maximum amount of memory they use to 4GB.

Up until the early 2000s, this much memory was more than enough for the average user. But with the advancements in hardware and applications, the 4GB ceiling soon became the minimum limit, with users quickly running out of RAM when multitasking.

On the other hand, 64-bit processors can work with 18.4 exabytes of memory, which is an excessively huge amount of RAM. To put that into perspective, one Exabyte is equal to 1,000,000 terabytes, bringing the maximum memory limit of x64 processors to 18.4 million terabytes!

Additionally, CPUs based on the x86 architecture only possess eight general-purpose registers, while their 64-bit counterparts have twice as many of these registers.

Operating systems and applications

Modern-day apps may not even run on 32-bit systems

A screenshot showing the Windows 11 Blossam wallpaper with the dark theme enabled.

Back when Microsoft unveiled Windows 11, there was a huge outrage from the community as the newest version of the OS had some beefier minimum requirements. While you could ignore some, like TPM 2.0, there’s no way to run it on older 32-bit systems as Microsoft never released x86 builds for its flagship OS. This meant you couldn’t upgrade past the 32-bit versions of Windows 10 on systems that use the old architecture.


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32-bit operating systems also have some other limitations. Aside from some workarounds on Linux, x86 versions of Windows couldn’t even dedicate the full 4GB of RAM to an application. Since Windows reserves some memory for background processes, you’ll see reduced performance when running a particularly demanding application on a 32-bit system. Plus, the 64-bit versions of many apps, which require 64-bit DLL files, may not even work on 32-bit systems, let alone provide decent performance.

64-bit vs 32-bit CPUs: It’s more than just a number

Today, almost every consumer PC is powered by a 64-bit processor, so you’re not likely to come across new systems equipped with 32-bit chips. You might be wondering, why don’t we have more powerful 128-bit and 256-bit processors when the shift to 64-bit architecture brought significant upgrades to the computing landscape? The thing is, 128-bit CPUs are plausible, but there’s no need for them to go mainstream just yet because we don’t require obscenely large amounts of RAM in consumer systems. In an age where even the premium gaming PCs won’t need more than 256GB of memory, it’s safe to say that we won’t hit the 18,400,000 TB RAM limit on 64-bit processors anytime soon.


Why we don’t have 128-bit CPUs

We went from 8-bit, to 16-bit, to 32-bit, and ended things at 64-bit. Here’s why 128-bit CPUs don’t exist.


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