KB2581464 : Increase Maximum Transfer Size Of USB Storage Devices

Just in case you are still using USB2.0 devices, you may be interested in getting the hotfix KB2581464.

KB2581464 includes a new feature that enables you to update the maximum transfer size  of USB storage devices in Windows 7 or in Windows Server 2008 R2. After you install this update, you can increase the maximum transfer size from 64 kilobytes (KB) to 2 megabytes (MB) in the Usbstor.sys driver.  For some USB storage devices, performance can be improved if the maximum transfer size is increased from the default 64 KB.

After installing the hotfix, perform the following steps:

  1. Click ‘Start’ and type ‘regedit’ in windows 7 search box,press enter.
  2. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\usbstor
  3. Create a new sub-key VVVVPPPP under usbstor, where
    • VVVV represents device descriptor idVendor in hexadecimal.
    • PPPP represents device descriptor idProduct in hexadecimal.
  4. In right side panel,right click select ‘New’ -> ‘DWORD Value’,give a name as ‘MaximumTransferLength‘.
  5. Double click ‘MaximumTransferLength’,set Base to Decimal and key in Value data to 2097120.7.
  6. Then restart PC again.That all.

To get the VVVV and PPPP for your USB device, you can use tool likeUSB Flash Benchmark that can be obtained from http://usbflashspeed.com/.

Hope this help.

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