How to determine the type of processor that your Windows Server 2003 x64-based computer or your Windows XP Professional x64-based computer uses

This article describes how to determine the processor type of a computer that is running any one of the following operating systems:

• Microsoft Windows Server 2003, Enterprise x64 Edition
• Microsoft Windows Server 2003, Standard x64 Edition
• Microsoft Windows Server 2003, Datacenter x64 Edition
• Microsoft Windows XP Professional x64 Edition

Information about the processor type is stored in the PROCESSOR_IDENTIFIER registry entry in the following registry subkey: The PROCESSOR_IDENTIFIER registry entry uses a string value that is described as follows:

• If the string value contains "AMD64" (without the quotation marks), the computer has an Advanced Micro Devices (AMD) AMD64 processor.
• If the string value contains "EM64T" (without the quotation marks), the computer has an Intel Extended Memory 64 Technology (EM64T) processor.

Note The value of the PROCESSOR_ARCHITECTURE registry entry in the following registry subkey is set to AMD64 regardless of the type of processor that the computer uses: To determine the processor type, use one of the following methods.

Method 1: Use the set command

To use the set command to determine the processor type, follow these steps:

1. Click Start, click Run, type cmd in the Open box, and then press ENTER.
2. At the command prompt, type set, and then press ENTER.
3. Note the string that is displayed next to PROCESSOR_IDENTIFIER.

Method 2: Use Registry Editor

To use Registry Editor to determine the processor type, follow these steps:

1. Click Start, click Run, type regedit in the Open box, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment
3. In the right pane, note the string that is displayed in the Data column for the PROCESSOR_IDENTIFIER registry entry.
4. Quit Registry Editor.

For more information about Windows Server 2003 x64 editions, visit the following Microsoft Web site: For more information about Windows XP Professional x64 Edition, visit the following Microsoft Web site:

Technical support for x64-based versions of Microsoft Windows

Your hardware manufacturer provides technical support and assistance for x64-based versions of Windows. Your hardware manufacturer provides support because an x64-based version of Windows was included with your hardware. Your hardware manufacturer might have customized the installation of Windows with unique components. Unique components might include specific device drivers or might include optional settings to maximize the performance of the hardware. Microsoft will provide reasonable-effort assistance if you need technical help with your x64-based version of Windows. However, you might have to contact your manufacturer directly. Your manufacturer is best qualified to support the software that your manufacturer installed on the hardware.

For product information about Microsoft Windows XP Professional x64 Edition, visit the following Microsoft Web site: For product information about x64-based versions of Microsoft Windows Server 2003, visit the following Microsoft Web site: