Applies ToWindows Vista Home Basic Windows Vista Home Premium Windows Vista Ultimate Windows Vista Business Windows Vista Enterprise Windows Vista Home Basic 64-bit Edition Windows Vista Home Premium 64-bit Edition Windows Vista Ultimate 64-bit Edition Windows Vista Business 64-bit Edition Windows Vista Enterprise 64-bit Edition Windows Server 2008 Datacenter without Hyper-V Windows Server 2008 Enterprise without Hyper-V Windows Server 2008 for Itanium-Based Systems Windows Server 2008 Standard without Hyper-V Windows Server 2008 Datacenter Windows Server 2008 Enterprise Windows Server 2008 Standard Windows Server 2008 Web Edition

Symptoms

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.

Resolution

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:

935791 How to obtain the latest Windows Vista service pack

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

File name

File version

File size

Date

Time

Platform

Netiomig.dll

6.0.6000.20571

49,152

03-Apr-2007

12:51

x86

Netiougc.exe

6.0.6000.20571

22,016

03-Apr-2007

12:04

x86

Tcpip.sys

6.0.6000.20571

803,328

03-Apr-2007

12:05

x86

Tcpipcfg.dll

6.0.6000.20571

167,424

03-Apr-2007

12:51

x86

Windows Vista, 64-bit versions

File name

File version

File size

Date

Time

Platform

Netiomig.dll

6.0.6000.20571

59,904

03-Apr-2007

14:03

x64

Netiougc.exe

6.0.6000.20571

25,600

03-Apr-2007

12:35

x64

Tcpip.sys

6.0.6000.20571

1,193,472

03-Apr-2007

12:36

x64

Tcpipcfg.dll

6.0.6000.20571

232,960

03-Apr-2007

14:03

x64

Status

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.

More Information

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

  • 328890 New registry entry for controlling the TCP Acknowledgment (ACK) behavior in Windows XP and in Windows Server 2003  

  • 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.

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:

824684 Description of the standard terminology that is used to describe Microsoft software updates

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