Use any USB 2.0 Device for Readyboost in Vista

Martin Brinkmann
Apr 16, 2007
Updated • Jun 12, 2013
Windows, Windows Vista

Readyboost is a disk caching system introduced in Windows Vista that relies on flash memory to boost system performance. The effect is not that noticeable, especially not on systems that have enough system memory, but some users swear on it and I do not want to drag this into a discussion of Readyboost's usefulness.

If your PC has less than 1 Gigabyte or so of RAM installed, it may help you get that extra boost that you may require.

The USB device has to meet specific requirements for use as a Readyboost device which are mostly performance related. The majority of older USB devices do not meet those requirements so that they can't be selected in the configuration menu.

There is however a trick that enables many USB devices for Readyboost even though they do not pass the initial test that Windows performs to find out if a device is suitable.

To do that do the following.

  1. Right-click the device that you want to use for Readyboost and select properties.
  2. Switch to the Readyboost tab and uncheck "Stop retesting this device when I plug it in".
  3. The old test values are stored in the registry which means that we have to edit some settings there to make Vista believe that the USB device meets all of the requirements.
  4. Unplug the device from the computer before you proceed.
  5. Open the Windows Registry editor by pressing Windows and R at the same time, typing in regedit in the run box and tapping on the enter key to load the editor. Note that you may receive an UAC prompt that you need to accept before you can continue.

Go to the key HKLM (Local Machine) -> SOFTWARE -> Microsoft -> Windows NT -> CurrentVersion -> EMDgmt which displays a list of all known USB devices on your computer.

Choose the one that you want to use for Readyboost and edit the following keys in the right pane:

  • Device Status - Change that value to 2
  • ReadSpeedKbs - Change the value to 1000
  • WriteSpeedKbs - Change the value to 1000 as well

After that is done you can use the USB device for Readyboost.

With RAM prices on a new low currently, it may make more sense to buy some RAM instead. Still, if you do not want that or cannot do so because the RAM is already maxed out, you may want to give Readyboost a try.


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  1. One American said on August 5, 2011 at 8:59 pm

    I want you to know that I installed this on a notebook with a 2 Gig max and noticd the difference right away. This is a game changer. I had no idea what ready boost was.

    Thank You.

  2. Serious Sam said on September 28, 2007 at 10:41 pm

    and i have connected it to an external usb case

  3. Serious Sam said on September 28, 2007 at 10:40 pm

    i have a western digital 40 gb hard drive which i want to use as the ready boost hard drive but it isnt in the location that u wrote above can u help me find it

  4. johntash said on April 18, 2007 at 6:38 am

    Cool. I wanted to try out the readyboost thing with my 4gb stick but it wouldn’t let me. Maybe I’ll actually test it out now. Thanks man

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