QUOTE(XP_2600 @ Nov 8 2007, 04:24)

My question is i think something like readyboost is something should be integrated deeply in the Kernel, so how its possible for a third party software to offer the same function ?, i like to know your opinion guys.
Why would it need to be an embedded kernel task? It just needs to keep track of what gets loaded from disk most often, and redirect the pointers to the more frequently accessed files to the removable drive, copy them over, and actively encrypt them. A kernel process would certainly be faster and better at it, but it's nothing that can't be done at the application layer.
As to the question of why it's not done in ram, that's easy: you have a practical limit on the amount of RAM in your system - 4GB on most boxes currently, and it costs a couple hundred bucks to get there. There is no such limit on flash storage, and a 512MB stick dedicated to this process costs you around $15 (and can never end up being commandeered by a game or photoshop).
Vista DOES use system RAM for application caching, that process is called SuperFetch. It does pretty much exactly the same thing as ReadyBoost, but in RAM. The thing is, as RAM gets used, it drops the cached files, and as the RAM gets released, it has to load the cache back from disk. ReadyBoost acts as a "launch pad" that can make that process more efficient, because SuperFetch can pull from the faster flash drive rather than having to go back to disk.
This is why there's a limit to the gain you get with it based of the amount of system RAM and the speed of your system. If you have more RAM, there's less interaction between ReadyBoost and Superfetch, and if you have less RAM, SuperFetch can only make use of smaller amounts of ReadyBoost space as it's cahcing less. A faster processor sees less impact because the process of moving items to and from system RAM take so much less time. A Vista machine with 768MB of RAM and a 2GHz P4, with a 512MB ReadyBoost cache will see a much larger boost from it than a 3GHz C2D wth 4GB or RAM and a 4GB ReadyBoost cache will, or a 1.4GHz P3 with 512MB RAM and a 256MB ReadyBoost, because ReadyBoost really plays to the weaknesses of the first machine, while the second really has no weakness to help with, and the third is simply too weak to be able to effectively utilize it.