Processor and memory capabilities of Windows XP Professional x64 Edition and of the x64-based versions of Windows Server 2003

This article contains information about the capabilities of Microsoft Windows XP Professional x64 Edition and of the x64-based versions of Microsoft Windows Server 2003. To illustrate this information, this article compares the support that is provided by the x64-based versions to the support that is provided by the 32-bit versions of Windows Server 2003 and of Windows XP Professional in the following areas:

• The number of processors
• The amount of physical random access memory (RAM)
• The memory allocation settings

The number of processors and the amount of physical RAM that are supported

The following table compares the number of processors and the amount of physical RAM that are supported by the x64-based versions of Windows Server 2003 and by Windows XP Professional x64 Edition to those that are supported by the 32-bit versions.Notes 

• x86-based versions of Windows Server 2003 that are running on a computer that uses a multicore processor or a hyper-threading processor support a maximum number of 32 logical processors.
• x64-based versions of Windows Server 2003 that are running on a computer that uses a multicore processor or a hyper-threading processor support a maximum number of 64 logical processors.

Memory allocation settings

The following table compares the memory allocation settings that are supported by the x64-based versions of Windows Server 2003 and Windows XP Professional x64 Edition to those that are supported by the 32-bit versions. For more information about the x64-based versions of Windows Server 2003, 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

If your hardware came with a Microsoft Windows x64 edition already installed, your hardware manufacturer provides technical support and assistance for the Windows x64 edition. In this case, your hardware manufacturer provides support because a Windows x64 edition was included with your hardware. Your hardware manufacturer might have customized the Windows x64 edition installation by using 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 a Windows x64 edition. 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. If you purchased a Windows x64 edition such as a Microsoft Windows Server 2003 x64 edition separately, contact Microsoft for technical support.

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: