Microsoft KB Archive/940021

= The data transfer speed of a USB 1.x device may be slower than expected when you connect it to a USB 2.0 hub on a Windows XP SP2-based computer =

Article ID: 940021

Article Last Modified on 7/12/2007

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APPLIES TO

 Microsoft Windows XP Service Pack 2, when used with:  Microsoft Windows XP Professional

 Microsoft Windows XP Home Edition  Microsoft Windows XP Service Pack 1, when used with:  Microsoft Windows XP Professional

 Microsoft Windows XP Home Edition</li></ul> </li></ul>

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<div class="symptoms_section">

SYMPTOMS
When you connect a USB 1. device to a USB 2.0 hub on a Microsoft Windows XP Service Pack 2 (SP2)-based computer, the data transfer speed of the USB 1. device may be slower than expected.

Note This problem may also occur on a Windows XP Service Pack 1 (SP1)-based computer after you install the hotfix that is described in the following Microsoft Knowledge Base article:

810090 Universal serial bus devices may not always be detected when you start or resume the computer in Windows 2000 or in Windows XP

<div class="cause_section">

CAUSE
This problem occurs because of a change in the way that Windows XP handles certain types of data transfers, as described in Microsoft Knowledge Base article 810090.

<div class="workaround_section">

WORKAROUND
To work around this problem, connect the USB 1. device directly to the root universal serial bus (USB) port on the computer.

<div class="status_section">

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

Keywords: kbexpertiseinter kbtshoot kbprb KB940021

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