Some facts & fiction : Windows Vista (and Windows 7) includes a new feature called ReadyBoost (actually ReadyBoost for hard drives already exists; it’s called “page files”). Please note that this does not put the paging file onto a flash disk; the file is still backed on disk; this is a cache. If the data is not found in the ReadyBoost cache, it falls back to the HDD. With this feature, you can speed up your PC, with a USB memory !

Windows supports the following form factors for ReadyBoost:

• USB 2.0 fl ash disks
• Secure Digital (SD) cards
• CompactFlash cards

Normally windows uses a portion of your hard disk as a sort of a scratch pad, writing temp data to it while it works. But hard drives are much slower than memory. So the ReadyBoost feature lets you use a USB drive (or any of the 3 above) instead. As soon as you plug it in, you get a popup screen asking you to open the files or to ‘speed up the system’. clicking on the latter lets your USB drive act as a ‘scratch-pad’.

ReadyBoost takes advantage of the fact that flash memory offers lower seek times than hard disks. essentially that means that your system can get to a given location on a flash disk more quickly than it can to a corresponding spot on a hard disk. Hard disks are faster for large sequential reads; flash disks are quicker for small, random reads.

But which USB drive ? Anyone just wont do ! It has to be compatible.

The baseline requirements are :
The USB Key must be at least USB 2.0
The device must be able to do 3.5 MB/s for 4 KB random reads uniformly across the entire device and 2.5 MB/s for 512 KB random writes uniformly across the device.
The USB Key has to have at least 230mb of free space

The ReadyBoost Compatibility List is a pretty exhaustive list of some ReadyBoost compatible drives.

How much of a boost can you really expect from Ready Boost ? Well, as with so many other performance issues, it depends. If your internal memory is above the amount you actually need, Ready Boost won’t do much for you. If not, expect to see some REAL improvement !

There are several ways being suggested on the net as to how to make your USB compatible with some hacks/tweaks. Here is one I came across, for eg :

• Plug the device and open the device properties : Start > My Computer > Right click Device > Properties > Readyboost Tab
• Select, “Stop retesting this device when I plug it in.” Remove the device.
• Open Regedit : Start > Type regedit in the search bar
• Go to HKEY_LOCAL_MACHINE / SOFTWARE / Microsoft /Windows-NT / CurrentVersion / EMDgmt

Change the Device Status to 2, ReadSpeedKBs to 1000, WriteSpeedKBs to 1000

• Re-Plug the device. Ready boost should work.

But using such methods only fools Vista into thinking that such USB drive are compatible. Expect no performance gains in such cases ! You also risk losing data if you remove the device before shutting it down in Vista. So always use ‘Safely Remove Hardware’ option. If your ‘Safely Remove Hardware dialog box’ does not appear, see Here.

In reality, you are not speeding up the operating system, since the computer is using the computer’s hard drive and not the USB memory for the Ready boost.