Windows Vista ReadyBoost

Enabling Vista ReadyBoost is really easy. Just attach the USB drive on any computer running Windows Vista (any edition). When the device has been installed by device manager, a window will pop up, asking you what to do with the new storage.

You click on "Speed up my system".

After clicking, the following properties window automatically opens. Here you have to click the radio button "Use this device".


Windows suggests an amount of memory to reserve, use this default.


After clicking OK, Windows will initialize the USB key for ReadyBoost in the background, running without any further user intervention.

What is ReadyBoost

ReadyBoost uses non-volatile flash memory to cache parts of the swapped out applications. This does not mean that the pagefile will be on flash. It is only a cached copy. It is safe to remove the USB key at any time, without any loss of data.

To be ReadyBoost certified (Windows Vista Logo “Storage-0009 WLP”) a flash memory device must support:

• 5 MB/sec throughput for random 4k reads across the entire device
• 3 MB/sec throughput for random 512k writes across the entire device

Since the cache could possibly contain sensitive data like passwords, all data written to the key is encrypted using 128-bit AES security.

Windows will create a file "ReadyBoost.sfcache" on the USB key. This file has the size of the storage you allocated, leaving a rest available for your own use.

The minimum size of a ReadyBoost device is 256 MB, the maximum 4 GB (maximum filesize on FAT32). Microsoft recommends an 1:1 ratio or better. So if you have 1 GB of RAM, you should use 1 GB of ReadyBoost. For 2 GB of RAM, use at least 2 GB of ReadyBoost.

From the Microsoft FAQ:
Q. What kind of performance gains will Windows ReadyBoost give me?
A. The amount and type of gains will differ based on the configuration of your PC and how you use your PC. For instance, if you have a lot of system memory and aren’t in the habit of keeping many Windows open at once, the gains will be more modest. But if you find yourself switching between applications frequently then ReadyBoost will have a more beneficial effect on your experience.

This is what Matt Ayers from Microsoft had to say in a blog post:
Although ReadyBoost offers several benefits, accelerating boot is not one of them. We rebuild the cache after every state transition [ed: this includes standby and hibernation]. [...] the benefits appear after the system has finished booting. At that point, the USB (or SD card or CF card or other flash source) caches small, frequently used pages to create a more consistently responsive OS. The configuration of 1GB RAM + 2GB ReadyBoost cache should show real benefits (it’s what I’m currently running).