Here are answers to some common questions about the 32-bit and 64-bit versions of Windows.

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What is the difference between 32-bit and 64-bit versions of Windows?

The terms 32-bit and 64-bit refer to the way a computer's processor (also called a CPU), handles information. The 64-bit version of Windows handles large amounts of random access memory (RAM) more effectively than a 32-bit system. For more details, go to A description of the differences between 32-bit versions of Windows Vista and 64-bit versions of Windows Vista online.

How can I tell if my computer is running a 32-bit or a 64-bit version of Windows?

To find out if your computer is running 32-bit or 64-bit Windows, do the following:

  1. Open System by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Maintenance, and then clicking System.

  2. Under System, you can view the system type.

Which version of Windows Vista should I install: the 32-bit version or the 64-bit version?

To install a 64-bit version of Windows Vista, you need a processor that's capable of running a 64-bit version of Windows. The benefits of using a 64-bit operating system are most apparent when you have a large amount of random access memory (RAM) installed on your computer (typically 4 GB of RAM or more). In such cases, because a 64-bit operating system can handle large amounts of memory more efficiently than a 32-bit operating system, a 64-bit operating system can be more responsive when running several programs at the same time and switching between them frequently.

For more information about the benefits of running 64-bit computers, go to Understanding 64-bit PCs online.

How do I tell if my computer can run a 64-bit version of Windows?

To run a 64-bit version of Windows, your computer must have a 64-bit-capable processor. To find out if your processor is 64-bit-capable, do the following:

  1. Open Performance Information and Tools by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Maintenance, and then clicking Performance Information and Tools.

  2. Click View and print details.

  3. In the System section, you can see what type of operating system you're currently running under System type. Under 64-bit capable, you can see whether you can run a 64-bit version of Windows. (If your computer is already running a 64-bit version of Windows, you won't see the 64-bit capable listing.)

Can I upgrade from a 32-bit version of Windows to a 64-bit version of Windows?

No. If you are currently running a 32-bit version of Windows, you can only perform an upgrade to another 32-bit version of Windows. Similarly, if you are running a 64-bit version of Windows, you can only perform an upgrade to another 64-bit version of Windows.

If you want to move from a 32-bit version of Windows to a 64-bit version of Windows Vista or vice versa, you'll need to back up your files and then choose the Custom option during Windows Vista installation. Then, you'll need to restore your files and reinstall your programs. For more information, see Installing and reinstalling Windows Vista.

For detailed information about installing and upgrading 32-bit and 64-bit versions of Windows, go to Installation choices for Windows Vista (32-bit) or Installation choices for Windows Vista (64-bit) online.

Notes

  • To install a 64-bit version of Windows on a computer running a 32-bit version of Windows, you'll need to start, or boot, your computer using a 64-bit Windows installation disc.

  • If you start your computer using a 64-bit Windows installation disc, but your computer isn't capable of running a 64-bit version of Windows, you'll see a Windows Boot Manager error. You'll need to use a 32-bit Windows installation disc instead.

Can I run 32-bit programs on a 64-bit computer?

Most programs designed for the 32-bit version of Windows will work on the 64-bit version of Windows. Notable exceptions are many antivirus programs.

Device drivers designed for 32-bit versions of Windows won't work on computers running a 64-bit version of Windows. If you're trying to install a printer or other device that only has 32-bit drivers available, it won't work correctly on a 64-bit version of Windows. If you are unsure whether there is a 64-bit driver available for your device, go online to the Windows Vista Compatibility Center.

Can I run 64-bit programs on a 32-bit computer?

If the program is specifically designed for the 64-bit version of Windows, it won't work on the 32-bit version of Windows. (However, most programs designed for the 32-bit version of Windows will work on the 64-bit version of Windows.)

Device drivers designed for the 64-bit version of Windows won't work on computers running a 32-bit version of Windows. To learn how to check for drivers, see Update a driver for hardware that isn't working properly or go to the device manufacturer's website.

How can I find programs and devices that work with the 64-bit version of Windows Vista?

You can go online to the Windows Vista Compatibility Center and check to see whether the program or device is compatible with the 64-bit version of Windows Vista.

If I'm running a 64-bit version of Windows, do I need 64-bit drivers for my devices?

Yes, all hardware devices need 64-bit drivers to work on a 64-bit version of Windows. Drivers designed for 32-bit versions of Windows won't work on computers running 64-bit versions of Windows.

If you are unsure whether there is a 64-bit driver available for your device, see Update a driver for hardware that isn't working properly or go to the device manufacturer's website.

You can also go online to the Windows Vista Compatibility Center, or get information about drivers by going to the Windows Vista Upgrade Advisor website.