The behavior of TCP acknowledgments (ACKs) does not change after you modify the TcpAckFrequency registry entry in Windows Vista

On a computer that is running Windows Vista, you modify the TcpAckFrequency registry entry by following the steps that are described in Microsoft Knowledge Base article 328890. However, the behavior of TCP acknowledgments (ACKs) does not change.

Service pack information

To resolve this problem, obtain the latest service pack for Windows Vista. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Hotfix information

Prerequisites

There are no prerequisites.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

Registry information

You do not have to make any changes to the registry.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista, 32-bit versions

Windows Vista, 64-bit versions

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Windows Vista Service Pack 1.

For more information about the TcpAckFrequency registry entry, click the following article numbers to view the articles in the Microsoft Knowledge Base:

• 328890  (http://support.microsoft.com/kb/328890/ ) New registry entry for controlling the TCP Acknowledgment (ACK) behavior in Windows XP and in Windows Server 2003
• 823764  (http://support.microsoft.com/kb/823764/ ) Slow performance occurs when you copy data to a TCP server by using a Windows Sockets API program

For more information about TCP/IP registry values in Windows Vista and in Windows Server Code Name "Longhorn," see the "TCP/IP Registry Values for Microsoft Windows Vista and Windows Server 'Longhorn'" white paper. To obtain this white paper, visit the following Microsoft Web site:For more information about the terms that are used to describe software updates, click the following article number to view the article in the Microsoft Knowledge Base: