After you update your computer to Microsoft Windows XP Service Pack 2 (SP2), the performance of your 1394a or 1394b FireWire devices may be greatly decreased. A digital camera that uses S400 speed is an example of such a device. 
This problem occurs if you connect a 1394a or 1394b FireWire device to a 1394b port. This problem occurs because Windows XP SP2 changes 1394b ports to S100 speed when you upgrade. 
The following file is available for download from the Microsoft Download Center:

Download the Update for Windows XP (KB885222) package now