Microsoft KB Archive/906511

= You experience slow network performance in Windows 2000 or in Windows XP =

Article ID: 906511

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows 2000 Professional Edition
 * Microsoft Windows 2000 Server
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional

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Important This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry



SYMPTOMS
Consider the following scenario. You are using either a Microsoft Windows 2000-based computer or a Microsoft Windows XP-based computer. The computer has a high-bandwidth, high-delay network connection such as an Asymmetric Digital Subscriber Line (ADSL) network connection. When you perform network-related tasks, you experience slow network performance. For example, when you try to view Internet-based Web sites, these Web sites do not appear as quickly as you expect.



CAUSE
This issue occurs because the value of the TcpWindowSize registry entry is too small.



RESOLUTION
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To resolve this issue, follow these steps:  Click Start, click Run, type regedit in the Open box, and then click OK. Locate the following registry subkey:

 Click TcpWindowSize, and then click Modify on the Edit menu. In the Value data box, type a new value that is larger than the old value. The default setting for the TcpWindowSize registry entry is 8760 (Decimal) for Ethernet. The valid range for the TcpWindowSize registry entry is 0 through 65535 (Decimal). Typically, a larger value enables better network performance.



MORE INFORMATION
For more information about related topics, click the following article numbers to view the articles in the Microsoft Knowledge Base:

140552 How to optimize Windows NT to run over slow WAN Links w/TCP/IP

314053 TCP/IP and NBT configuration parameters for Windows XP

Additional query words: networking

Keywords: kbtshoot kbprb KB906511

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