Microsoft KB Archive/934314

= Performance is slower than you expect when you read from or write to an IEEE 1394 hard disk that uses a VIA Technologies 1394 host controller in Windows Vista =

Article ID: 934314

Article Last Modified on 8/29/2007

-

APPLIES TO


 * Windows Vista Ultimate
 * Windows Vista Enterprise
 * Windows Vista Business
 * Windows Vista Home Premium
 * Windows Vista Home Basic
 * Windows Vista Ultimate 64-bit Edition
 * Windows Vista Enterprise 64-bit Edition
 * Windows Vista Business 64-bit Edition
 * Windows Vista Home Premium 64-bit Edition
 * Windows Vista Home Basic 64-bit Edition
 * Windows Vista Starter

-



SYMPTOMS
Consider the following scenario. You connect an Institute of Electrical and Electronics Engineers (IEEE) 1394 hard disk to a Windows Vista-based computer that uses a VIA Technologies 1394 host controller. However, performance is slower than you expect when you read from the hard disk or write to the hard disk.

For example, you may experience decreased reading and writing performance of approximately 20 percent in Windows Vista when you compare it to Microsoft Windows XP with Service Pack 2 in the same test environment.



CAUSE
This issue occurs because high-speed 1394 physical-layer unit (PHY) mode is not enabled for the VIA 1394 host controller in Windows Vista.



Hotfix information
This hotfix is specific to the VIA 1394 host controller. This hotfix enables high-speed 1394 PHY mode for the VIA 1394 host controller.

A supported hotfix is now available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. To create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

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, 64-bit versions


STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.



MORE INFORMATION
For more information about terminology that is used to describe Microsoft 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

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.

Additional query words: drive device PnP chipset Serial Bus Protocol 2 SBP-2

Keywords: kbbug kbfix kbqfe kbpubtypekc kbexpertiseinter kbhotfixserver kbwinvistapostrtmfix KB934314

-

[mailto:TECHNET@MICROSOFT.COM Send feedback to Microsoft]

© Microsoft Corporation. All rights reserved.