KB2581464 : Increase Maximum Transfer Size Of USB Storage Devices For Windows 7

A new hotfix KB2581464 updated by Microsoft for Windows 7 and Windows Server 2008 R2 users to increase the maximum transfer size of USB storage devices.

KB2581464 :http://support.microsoft.com/kb/2581464/
Download KB2581464 :http://support.microsoft.com/hotfix/KBHotfix.aspx?kbnum=2581464&kbln=en-us

After you install this update, you can increase the maximum transfer size from 64 kilobytes (KB) to 2 megabytes (MB) for USB storage devices.


Install KB2581464 Hotfix

1. Download hotfix KB2581464 and installed, then reboot PC.

2. Click ‘Start’ and type ‘regedit’ in windows 7 search box, press enter.

3. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\usbstor

4. Create a new sub-key VVVVPPPP under usbstor.

5.In right side panel,right click select ‘New’ -> ‘DWORD Value’, give a name as ‘MaximumTransferLength‘.



6. Double click ‘MaximumTransferLength’, set Base to Decimal and key in Value data to 2097120.

USB transfer size


7.Then restart PC again. That all.

Below are the screenshot copy speed rate before and after applied hotfix which transfer a 649 MB size file to Buffalo external hard disk.


Hotfix increase USB transfer rate


Hotfix increase USB transfer rate


Noticed that Copy speed is 100% increase after applied the new hotfix.

PS : Not all the USB storage devices performance can be improve after applied this hotfix. This update supports this change when the hardware vendor provides a device information file (INF) to set this value for the USB storage devices.

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