Microsoft KB Archive/946765

= A description of the differences between 32-bit versions of Windows Vista and 64-bit versions of Windows Vista =

Article ID: 946765

Article Last Modified on 1/2/2008

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APPLIES TO


 * Windows Vista Business
 * Windows Vista Enterprise
 * Windows Vista Home Basic
 * Windows Vista Home Premium
 * Windows Vista Ultimate
 * Windows Vista Enterprise 64-bit Edition
 * Windows Vista Home Basic 64-bit Edition
 * Windows Vista Home Premium 64-bit Edition
 * Windows Vista Ultimate 64-bit Edition
 * Windows Vista Business 64-bit Edition

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INTRODUCTION
This article describes the differences between the 32-bit versions of Windows Vista and the 64-bit versions of Windows Vista.

Note To use a 64-bit version of Windows Vista, you must have a computer that has a 64-bit processor. Also, you must have 64-bit device drivers for the devices that are in the computer.



MORE INFORMATION
The main differences between the 32-bit versions of Windows Vista and the 64-bit versions of Windows Vista relate to memory accessibility, memory management, and enhanced security features. The security features that are available in the 64-bit versions of Windows Vista include the following:
 * Kernel Patch Protection
 * Support for hardware-backed Data Execution Protection (DEP)
 * Mandatory driver signing
 * Removal of support for 32-bit drivers
 * Removal of the 16-bit subsystem

One of the greatest advantages of using a 64-bit version of Windows Vista is the ability to access physical memory (RAM) that is above the 4-gigabyte (GB) range. This physical memory is not addressable by 32-bit versions of Windows Vista.

Depending on the version of Windows Vista that is installed, a 64-bit version of Windows Vista supports from 1 GB of RAM to more than 128 GB of RAM. The ability to address more physical memory lets Windows Vista minimize the time that is required to swap processes in and out of physical memory. Therefore, Windows Vista can manage processes more efficiently. This memory management feature helps improve the overall performance of Windows Vista.

Advantages when you install a 64-bit version of Windows Vista

 * Increased memory support beyond that of the 4-GB addressable memory space that is available in a 32-bit operating system
 * Increased program performance for programs that are written to take advantage of a 64-bit operating system
 * Enhanced security features

What to consider when you install a 64-bit version of Windows Vista

 * 64-bit device drivers may not be available for one or more devices in the computer.
 * Device drivers must be digitally signed.
 * 32-bit device drivers are not supported.
 * 32-bit programs may not be fully compatible with a 64-bit operating system.
 * It may be difficult to locate programs that are written specifically for a 64-bit operating system.
 * Not all hardware devices may be compatible with a 64-bit version of Windows Vista.

The main differences between the 32-bit versions of Windows Vista and the 64-bit versions of Windows Vista
