64-bit programs run faster and more efficiently than 32-bit applications. Every reasonably modern PC has a 64-bit processor. But how do you run 32-bit software on a 64-bit computer?
Modern computers – made in recent years – are powered by 64-bit processors and operating systems and are only capable of running 64-bit applications. This is why the software provided today is almost exclusively 64-bit. You’ll still run into some 32-bit apps (especially if you’re using older apps), and running them on a 64-bit version of Windows is usually pretty seamless. So, how does it all work? Let’s find out.
Can you run 32-bit software directly on a 64-bit machine?
Understanding how a 64-bit architecture differs from a 32-bit system is a complex topic beyond the scope of this article. Just know that a 64-bit processor (and operating system) not only processes more information at once, but does it in a radically different way than a system with an older architecture.
So while apps designed for a 32-bit computer might seem to work just the same on a 64-bit machine, there’s more going on under the hood than just change compatibility mode† The environment expected by a 32-bit app does not exist in a 64-bit version of Windows, making it impossible for such an application to communicate directly with the hardware.
The solution? emulation. The only way to get a 32-bit program working is to mimic the old-fashioned architecture and give the app the same interface it was built for.
The default option: WOW64
Microsoft is well aware of the problem with running 32-bit apps on a 64-bit operating system. This is why modern operating systems with 64-bit architecture such as Windows XP, Vista, Windows 7 or Windows 10 come with a built-in emulator called WOW64.
WOW64 is a Windows subsystem designed to run 32 applications on a 64-bit machine. WOW64 simulates the environment of a 32-bit operating system and provides older applications with the interface found in earlier Windows versions.
This compatibility layer is lightweight, powerful and works right out of the box. This means that you can just double-click the EXE file of a 32-bit application and let Windows do the rest.
An expensive alternative: virtualization
Virtual machines are a well-known method of running various architectures and operating systems on hardware not designed to support it. You can install and run apps intended for Linux or Apple’s macOS on a Windows PC with an Intel processor without major changes.
You can use the same technique to run an older, 32-bit version of Windows on your modern PC. This allows you to run older applications on your system, even if your current processor is 64-bit.
However, remember that this method involves a lot of work and, frankly, is not necessary. It’s much easier to use the built-in WOW64 emulator than to look for a copy of 32-bit Windows XP.
Installing 32-bit apps on a 64-bit computer
There is no difference between installing a 32-bit application on a 32-bit operating system versus a 64-bit version of Windows. Whether you have a CD-ROM or an installation file, you just run the installation and let the operating system sort it out.
Windows handles 32-bit versions of programs by placing them in a different folder. There is the default Program Files folder, which contains all the 64-bit software you have installed, and a Program Files (x86) containing apps intended for a 32-bit machine.
The software in the x86 directory is run by emulating a 32-bit version of Windows using WOW64. This process is fully automatic, so you can run apps present in both program files without any difference.
Can you run 32-bit apps on a 64-bit CPU?
Many people think that old programs can only run on a 32-bit processor. While it is true that only a 32-bit computer can run these apps natively, all modern system types can run such programs just as well.
For most users, this comes down to simply running the said app as Windows itself will take care of the technicalities of emulating via WOW64. If you want a different approach (maybe if the tool doesn’t work for you), you can use virtualization.
Services like VirtualBox or VMWare allow you to emulate a 32-bit virtual machine, which can run all 32-bit apps directly. This is a complicated process, even with tutorials, so you’d better get WOW64 working normally on your Windows installation.