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General FAQs About 64-bit Windows

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The General section of FAQs for ISVs provides resources on where to find more information about 64-bit Windows, a few specifications, administration, and some information about what to expect in the near future.

Topics on this page:

  • Specifications
  • Requirements
  • Administration
  • 64-bit Strategy
  • Additional Information and Resources

 

Specifications

  • Which Microsoft operating systems work on an x64-based system?
    Windows XP Professional x64 Edition; Windows Server 2003, Standard x64 Edition; Windows Server 2003, Enterprise x64 Edition; and Windows Server 2003, Datacenter x64 Edition. For more information, please see the Windows XP Professional x64 Edition Overview and the Windows Server 2003 x64 Editions Product Overview.

  • What are the General Memory Limits of Windows 64-bit?
    The memory limits for 64-bit Windows are:

    • Total Virtual Address Space: 4 GB (32-bit) and 8 TB (64-bit)
    • Virtual Address Space per 32-bit processes: 2 GB (4 GB with /LARGEADDRESSAWARE) (3 GB with /LARGEADDRESSAWARE before SP1)
    • Virtual Address Space per 64-bit processes: 8 TB (2 GB with /LARGEADDRESSAWARE:NO) (7 TB on Itanium) For more information, see Memory Limits for Windows Releases.

  • What are the memory and CPU limits of 64-bit Windows editions?

     

      Maximum RAM*   Maximum CPUs*
    Edition 32-bit 64-bit   32-bit 64-bit
    Windows XP Professional 4 GB 128 GB   2 2
    Windows Server 2003 Standard Edition 4 GB 32 GB   4 4
    Windows Server 2003 Enterprise Edition 32/64 GB** 1 TB   8 8
    Windows Server 2003 Database Edition 64/128 GB** 1 TB   32 64
    \* These are the limits of the Windows operating system. Hardware limits and restrictions might be different. \*\* Extended with Windows Server 2003 Service Pack 1.

    Requirements

    • What processors work with Windows 64-bit operating system?
      64-bit editions of Windows run on the AMD Opteron, AMD Athlon 64, Intel Xeon EM64T, Intel Pentium 4 with EM64T, and Intel Itanium processors (including the Itanium2).

    Administration

    • How does an Administrator access redirected folders?
      The article “Enabling the administrator to have access to redirected folders” discusses the Folder Redirection feature and how it can be used, particularly by administrators. For more information, please see Knowledge Base article 288991.
    • How do I stop the Folder Redirection for one or more users?
      After you have successfully deployed a Folder Redirection Group Policy object (GPO) for your site, you may want to stop Folder Redirection for one or more users. For more information, please see Knowledge Base article 888203.
    • Why am I seeing unexpected computer account group memberships when running Gpresult.exe and using the command line tool?
      When you run the Gpresult.exe command-line tool on a Microsoft Windows Server 2003-based domain controller, the following unexpected computer account group memberships may be displayed:
      • Administrators
      • Everybody
      • Authenticated Users For more information, please see Knowledge Base article 889501.
    • My Windows Server is experiencing high CPU usage and Task Manager shows multiple instances of Wmiprvse.exe. What might be causing this problem?

    Installation

    • Why am I having problems installing the Operating System if I'm using the latest SCSI or IDE controller technology?
      If you get the error message— Setup did not find any hard disk drives installed in your system. If you are upgrading by using the Winnt32.exe file, or if you are performing a new installation by using the Winnt.exe file, you receive the following Stop error: Stop 0x0000007B Inaccessible_boot_device —when installing Microsoft Windows XP Professional x64 Edition or Microsoft Windows Server 2003 on a new computer or on a computer that has the latest SCSI or IDE controller technology, you may have to use an OEM device driver to support, for example, a new mass storage controller, to continue with the installation. The symptoms that you may have installing an OEM device driver include the following:
      • The computer may keep restarting and never start the GUI installation after the text mode Setup is finished.
      • The Setup program may stop, and you may receive an error message if the Setup program does not correctly detect the controller.
      • If you are booting from the installation floppy disks or CD-ROM disc. For more information, please see Knowledge Base article 314859.
    • Where can I learn more about the Remote Installation Service (RIS) functionality in Windows Server 2003?
      The article “Updated Remote Installation Service functionality in Windows Server 2003 Service Pack 1” describes the new Remote Installation Services (RIS) changes that are made available on a computer that is running a 64-bit version of Microsoft Windows Server 2003 Service Pack 1 (SP1) and how to deploy 64-bit operating system images in an enterprise environment. Additionally, this article describes the new features and functionality of the Risetup.exe and Riprep.exe tools, the Client Installation Wizard, and the x8664.osc screen. For more information, please see Knowledge Base article 891128.
    • How do I uninstall Windows 64-bit Operating System?
      Uninstalling an operating system generally requires the use of the Fdisk tool and the Format tool to partition or repartition a hard disk. For more information, please see Knowledge Base article 255867.
    • How do I determine the appropriate page file size for 64-bit versions of Windows?
      When you set up a 64-bit version of Microsoft Windows Server 2003 or Microsoft Windows XP, the operating system will create a page file that is one and a half times the amount of RAM that is installed in your computer. However, as the amount of RAM in a computer increases, the need for a page file decreases. For more information, please see Knowledge Base article 889654.

    Backup/Restore

    • What utility can I use to backup my system?
      Use ntbackup: start->run->ntbackup to backup 32-bit and 64-bit files on 64-bit Windows operating systems. For other backup utilities, please see your preferred vendor.
    • Why do I receive Event ID 1168 and 1003 error messages when booting an Active Directory domain controller following restoring of the Active Directory database?
      If you get the error message— Directory Services could not start because of the following error: The system cannot find the file specified. Error status: 0xc000000f. Please click Ok to shutdown this system and reboot into Directory Services Restore Mode, check the event log for more detail information. —when booting an Active Directory domain controller into normal mode following the restoration of its Active Directory database it is likely that the Active Directory database file, Ntds.dit, does not exist in the folder referred to by the DSA Database File setting in the registry. For more information, please see Knowledge Base article 280364.
    • Will my 32-bit backup and restore application work in 64-bit Windows?
      Backup applications written for 32-bit versions of Microsoft Windows will not properly backup or restore system files and settings when run on 64-bit systems due to:
      • The Volume Shadow Copy Services (VSS) functionality is different between Windows XP for 32-bit systems and Windows XP for 64-bit systems
      • The file system filter driver creates a virtual representation of the system files
      • 32-bit applications will be able to select the right version of system files to copy to backup media
      • 32-bit applications will fail when using Automatic System Recovery (ASR) to prepare a full system backup on 64-bit systems Microsoft is working with many ISVs to help them make their applications compatible with 64-bit editions of Windows. This applies to Microsoft Windows XP 64-Bit Edition and Microsoft Windows Server 2003, 64-Bit Enterprise Edition.

    Networking

    • Why am I getting an "Access Denied" error message when trying to access remote resources?
      If the network logon information is cached to login to a computer and establish a remote access connection, then access to remote resources is attempted, you may receive the following error message: "Access denied". This issue may occur if you connect to the remote network through a third-party implementation of the Remote Authentication Dial-In User Service (RADIUS) protocol. For more information, please see Knowledge Base article 822707.
    • Why do I not see any network connection icons in the Network Connections folder?
      When you open your Network Connections folder in Microsoft Windows XP, you find that your network connections are not listed. The network connection icons are missing, including the wireless network connection icon. The following conditions might be true:
      • There is an invalid entry in the Rasphone.pbk file. A third-party program might have created invalid entries in the Rasphone.pbk file.
      • You have installed the hotfix that is described in Microsoft Knowledge Base article 829652. For more information, please see Knowledge Base article 894543.

    64-bit Strategy

    Why should I move from a 32-bit to a 64-bit operating system?

    Here are a few of the reasons to move to 64-bit Windows:

    • Faster File I/O: 64-bit architecture takes advantage of larger data blocks.
    • More Virtual Memory: there is up to 16 TB of virtual memory available for applications.
    • Higher Data Transfer Rates: due to more available concurrent processes.
    • Higher Transaction Handling Rates: due to the availability to handle more simultaneous client connections to a server.
    • Large file system: the 64-bit file systems allow the possibility of multi-exabyte sized files.

    How can I determine if my application should be ported to 64-bits?

    If you can answer “yes” to any of the following questions, the application might benefit from being ported to 64 bits.

    • Does the application require high I/O throughput or memory-intensive operations?
    • Does the application take advantage of parallel execution?
    • Is higher scalability needed to meet the workload demand?
    • Will the application be deployed into a 64-bit operating environment?

    What are some obstacles to running a 32-bit application in 64-bit mode?

    Some of the obstacles of running a 32-bit in 64-bit mode are:

    • Porting all 32-bit in-proc components to be 64-bit (or making them out-of-proc)
    • Data Misalignment
    • Member Realignment
    • Pointer Truncation

    Additional Information and Resources

    • Is the Windows Genuine Advantage program supported in x64?
      Yes. The Windows Genuine Advantage program verifies that you have a genuine copy of the Microsoft Windows operating system installed on your computer. For more information, please see Knowledge Base article 892130.
    • Where can I learn more about successful migrations to 64-bit Windows?
      Microsoft has a number of case studies on successful 64-bit migrations. They can be found at:
      • JNetDirect, Hands-on Lab Drives JNetDirect to 64-bits (August 17, 2004)
      • 64-Bit Computing Makes Number Crunching as Easy as 123 for Multimedia Content Services Provider (July 24, 2003)
      • 80 Percent More Computing Power for VTG-LEHNKERING AG (March 5, 2004)
      • CPG and Healthcare Market Research Provider Realizes Large Performance and Scalability Gains with 64-Bit SQL Server 2000 (April 24, 2003)
      • Swiss Institute of Bioinformatics Teams with Intel and HP and Deploys HP Cluster of Itanium 2-Based Servers to Accelerate Life Sciences Advances (4 pages .pdf)
      • SQL Server 2000 (64-bit) Case Studies
    • How do I find out what others are experiencing with Windows Server 2003 x64 Edition?
      To help you resolve technical questions while evaluating Windows Server 2003 x64, Microsoft has established newsgroups, based on your locale. You can access the Newsgroups for Windows Server from the “Training and Events” area of the Windows Server 2003 x64 site.
    • Why does my infrared data connection fail to transfer data?
      Data Transfer may fail when using National Semiconductor Infrared Data Association (IrDA) device that has a Plug and Play ID of *NSC6001. For more information, please see Knowledge Base article 891996.
    • Are there Webcasts on 64-bit Windows?
      Yes. Listed below are some of the Webcast topics available online, part of the Gearing Up for 64-Bit Computing on Windows Server Webcast series.

    What’s Next?

    • How do I obtain the release version of Window XP 64-bit edition?
      Windows XP x64 is an OEM release and Microsoft currently has no plans for a retail release.

    Resources