How to enable UDMA66 mode on Intel chipsets (247951)

SUMMARY

By default, the UDMA66 mode is disabled on a computer that is running Microsoft Windows when the computer uses a Intel chipset that supports UDMA66. This behavior is by design.

Enable the UDMA66 mode

• Make sure that the device supports UDMA66 mode.
• Use an 80-pin IDE cable with the correct pin cut.
• Add the following registry key:
  
  Important This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

  256986 Description of the Microsoft Windows registry

  1. Start Registry Editor.
  2. Locate the following key in the registry:

     HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Class\{4D36E96A-E325-11CE-BFC1-08002BE10318}\0000

  3. On the Edit menu, click Add Value, and then add the following registry value:

        Value Name: EnableUDMA66
        Data Type:  REG_DWORD
        Value:      1				

  4. Quit Registry Editor.
  5. Restart the computer.

Note For more information about the IDE cable, contact the hardware manufacturer.

When you restart your computer, the UDMA66 mode will be enabled if the mode is supported by the hardware.