Putting ReadyBoost To Work

Testing, like the thorough review of ReadyBoost done by Tom's Hardware Guide, proves there's no substitute for system RAM. But, particularly on PCs with minimal system memory (around 512MB or so) nothing helps more than plugging in a ReadyBoost-compatible flash drive.

Setting up a flash device for ReadyBoost is simple: In the device Properties, set the amount of space to set aside as a cache, and select "Use this device." (Click image to enlarge.)

Setting up ReadyBoost on a PC is about as hard as feeding a hamburger to a hungry dog. The most important thing to remember is to get your fingers out of the way. All you need is a flash device fast enough to support ReadyBoost (more on that later). Plug the flash drive into a USB port, or the memory card into an appropriate slot, and Vista will open an Autoplay window inviting you to "Speed up my system using Windows ReadyBoost." All you have to do is accept the suggested size for the cache.

Once the cache file (it's named ReadyBoost.sfcache) is configured on the device, it will be used by Vista whenever it's available. This mean if you need to use the device for something else and remove it from the PC, you can do it without causing a problem -- just remember to click on the "Safely Remove Hardware" applet in the system tray. You can even delete the cache file (simply go back into the device's properties and select "Do not use this device") and then reconfigure it again later on.

Picking A Flash Device For ReadyBoost
You can use just about any kind of flash device that you can insert directly into your PC. That includes USB flash drives, Secure Digital cards, CompactFlash cards, and Memory Stick cards. You can't use cards inserted into external USB readers, or anything on a USB 1.0 or USB 1.1 port.

To work with ReadyBoost, a flash device has to have more than 256MB with 230MB of free space. It must also be faster than the average flash drive has been in the past -- it must perform random 4K reads at 2.5 megabytes per second or faster, and perform random 512K writes at 1.7MB or faster. You can use devices as large as 32GB for ReadyBoost and format it as either FAT or NTFS, but Vista will use a maximum of 4GB for the cache file because of compatibility with FAT32 file format restrictions. ("Enhanced for ReadyBoost" devices have to meet a higher standard: 5MB per second for random 4K reads and 3 MB for random 512K writes.)

If a flash device is too slow for ReadyBoost you'll see this message. Vista will retest a device each time you connect it unless you instruct it otherwise. (Click image to enlarge.)

Flash device makers have rushed "Enhanced for ReadyBoost" devices to market, but it's still early days for ReadyBoost compatibility. If you've got a device you'd like to try, Vista will let you know pretty quickly whether it's ReadyBoost-ready or not: Just plug it in and check the ReadyBoost pane in its Properties listing. If the device is not compatible, Vista hands out three kinds of gentle rejection: You'll be told the device is "plugged into an unsupported interface" (meaning something about it is probably USB 1.x), or that the device "must be greater than 256MB" (as with other things in life, size does matter), or you'll see the message below, which indicates it's just plain too slow:

There may be some work-arounds for slow drives. Vista will retest devices that fail the speed test, but once a device passes, it's good forever. One blogger claims to have squeeked a marginal flash drive past the test by formatting it as NTFS and compressing it. But you use slow devices at your peril.

Not all compatible devices are marked as such, and if you're looking to buy a flash drive to use as a ReadyBoost device and want to know whether it's compatible, a British Web designer has started a community-driven Web site to capture information and opinions on which ones are and which ones aren't.