What’s the Difference Between 32-bit and 64-bit Windows?

By Jason Fitzpatrick on March 22nd, 2011

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Whether shopping for a new computer or upgrading an old one, you’ve likely come across the the “64-bit” designation and wondered what it meant. Read on as we explain what Windows 64-bit is and why you’d want a piece of that 64-bit pie.

Starting with Windows 7, Microsoft has done an enormous amount to increase the popularity of 64-bit computing among home users, but many people are unclear on what exactly it means (and may not even realize they’re already running it). Today we’re taking a look at the history of 32-bit and 64-bit computing, whether or not your computer can handle it, and the benefits and shortcomings of using a 64-bit Windows environment.

A Very Brief History of 64-bit Computing

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Before we start dazzling you with interesting history, let’s get the basics down. What does 64-bit even mean? In the context of discussions about 32-bit and 64-bit personal computers the XX-bit format refers to the width of the CPU register.

The register is a small amount of storage where the CPU keeps whatever data it needs to access quickly for optimal computer performance. The bit designation refers to the width of the register. A 64-bit register can hold more data than a 32-bit register, which in turn holds more than 16-bit and 8-bit registers. The more ample the space in the CPU’s register system, the more it can handle—especially in terms of using system memory efficiently. A CPU with a 32-bit register, for example, has a ceiling of 232 addresses within the register and is thus limited to accessing 4GB of RAM. This may have seemed like an enormous amount of RAM when they were hashing out register sizes 40 years ago but it’s a rather inconvenient limit for modern computers.

Although it may seem like 64-bit computing is the new kid on the techno-wizardry block, it has actually been around for decades. The first computer to utilize a 64-bit architecture was the Cray UNICOS in 1985, which sets a precedent for 64-bit super computers (the Cray 1 is seen in the center of the photo above). 64-bit computing would remain the sole province of super computers and large servers for the next 15 or so years. During that time, consumers were exposed to 64-bit systems, but most were completely unaware of it. The Nintendo 64 and the Playstation 2, both seen in the photo above, had 64-bit processors a full 5 years before consumer level 64-bit CPUs and accompanying operating systems even made an appearance on the public radar.

Consumer confusion over what 64-bit means to them—and poor driver support from manufacturers—severely hampered the push towards 64-bit PCs throughout most of the 2000s. In 2001, Microsoft released Windows XP 64-bit edition. It was not widely adopted, save for those willing to deal with extremely limited driver support and a lot of headaches.

The following year, OS X Panther and a handful of Linux distributions began supporting 64-bit CPUs in varying capacities. macOS X didn’t fully support 64-bit for another five years with the release of OS X Leopard. Windows supported 64-bit in Windows Vista but, again, it wasn’t widely adopted. All around it was a bumpy road for 64-bit adoption among home users.

Two things turned the tide in the PC world. The first was the release of Windows 7. Microsoft pushed 64-bit computing heavily to manufacturers and gave them better tools—and a longer lead time—for implementing 64-bit drivers.

The second, arguably bigger, influence came from the way PC manufacturers marketed their PCs. Selling to people who may not fully understand the platforms they’re buying means marketers have to push certain, easy-to-understand numbers. The amount of memory in a PC is one of those numbers. A PC with 8 GB of RAM just seems better than one with 4 GB of RAM, right? And 32-bit PCs were limited to 4 GB of RAM. In order to offer PCs with higher amounts of memory, manufacturers needed to adopt 64-bit PCs.

Can Your Computer Handle 64-bits?

Unless your PC predates Windows 7, the chances are high that it supports a 64-bit version of Windows. You may even already be running a 64-bit version of Windows, and that’s a pretty easy thing to check. Even if you’re running a 32-bit version of Windows 10, you may be able to switch versions if you have 64-bit capable hardware.

The Benefits and Shortcomings of 64-bit Computing

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You’ve read a little on the history of 64-bit computing and your system check indicates you can run 64-bit Windows. Now what? Let’s run through the pros and cons of switching over to a 64-bit operating system.

What do you have to look forward to if you make the leap? Here are some of the enormous benefits to making the jump to a 64-bit system:

  • You can rock radically more RAM: How much more? 32-bit versions of Windows (and other OSes for that matter) are limited to 4096MB  (or 4GB) of RAM. 64-bit versions are theoretically capable of supporting a little over 17 billion GBs of RAM thanks to that spacious register system we talked about earlier. Realistically, Windows 7 64-bit Home editions are limited (because of licensing issues, not physical limitations) to 16GB of RAM and the Professional and Ultimate editions can rock up to 192GB of RAM.
  • You’ll see increased efficiency: Not only can you install more RAM in your system (easily as much as your motherboard can support) you’ll also see more efficient use of that RAM. Because of the nature of the 64-bit address system in the register and how Windows 64-bit allocates memory you’ll see less of your system memory chewed up by secondary systems (like your video card). Although you may only double the physical amount of RAM in your machine it will feel like way more than that because of the new efficiency of your system.
  • Your computer will be able to allocated more virtual memory per process: Under 32-bit architecture Windows is limited to assigning 2GB of memory to an application. Modern games, video and photo editing applications, and hungry applications like virtual machines, crave large chunks of memory. Under 64-bit systems they can have, brace yourself for another big theoretical number, up to 8TB of virtual memory. That’s more than enough for even the craziest of Photoshop editing and Crysis sessions. On top of the more efficient use and allocation of memory, applications optimized for 64-bit operating systems, such as Photoshop and Virtualbox, are super fast and take full advantage of the spaciousness of the processor and memory afforded to them.
  • You’ll enjoy advanced security features: Windows 64-bit with a modern 64-bit processor enjoys additional protections not available to 32-bit users. These protections include the aforementioned hardware D.E.P., as well as Kernel Patch Protection that protects you against kernel exploits, and device drivers must be digitally signed which cuts down on the incident of driver-related infections.

That all sounds wonderful, no? What about the shortcomings? Fortunately the list of shortcomings that come with adopting a 64-bit operating system is increasingly smaller as time goes on. Still there are a few considerations:

  • You can’t find 64-bit drivers for older but critical devices on your system: This one is a serious deal killer, but the good news is that it’s not as big a problem as it used to be. Vendors almost universally support 64-bit versions of the latest operating systems and devices. If you’re running Windows 8 or 10 and using hardware manufactured in the last five or so years, you shouldn’t have any trouble with hardware drivers. If you’re running Windows 7 or previous—or using very old hardware—you might have less luck. Have an expensive sheet-fed scanner from 2003 that you love? Too bad. You’re probably not going to find any 64-bit drivers for it. Hardware companies would rather spend their energy supporting new products (and encouraging you to buy them) than supporting older hardware. For small things that are easily replaced or need to be upgraded anyway, this isn’t a big deal. For mission critical and expensive hardware, it’s more important. You’ll have to decide for yourself if the upgrade cost and tradeoffs are worth it.
  • Your motherboard doesn’t support more than 4GB of RAM: Although rare, it’s not unheard of to have a motherboard that will support an early 64-bit processor but not support more than 4GB of RAM. In this case you’ll still get some of the benefits of a 64-bit processor but you won’t get the benefit that most people crave: access to more memory. If you’re not buying bleeding edge parts, however, hardware has gotten so cheap lately that it might be time to retire the old motherboard and upgrade at the same time you’re upgrading your OS.
  • You have legacy software or other software issues to deal with: Some software doesn’t make the transition to 64-bit smoothly. While 32-bit apps run just fine on 64-bit Windows, 16-bit apps will not. If by some chance you’re still using a really old legacy app for something, you’ll need to either virtualize it or forgo an upgrade.

At some point, everybody’s going to be using a 64-bit version of Windows. We’re very nearly there, now. Still, even in these later stages of the 32-bit to 64-bit transition, there are a few speed bumps out there. Have any recent experience with 64-bit issues? We’d love to hear about it in the discussions.

Jason Fitzpatrick is a warranty-voiding DIYer who spends his days cracking opening cases and wrestling with code so you don't have to. If it can be modded, optimized, repurposed, or torn apart for fun he's interested (and probably already at the workbench taking it apart). You can follow him on if you'd like.

  • Published 03/22/11
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