The people from ran some tests on Windows Vista's new feature called ReadyBoost, a technology that claims to speed up Windows by plugging a USB flash drive into your PC in order to create a faster, flash drive-based cache of Windows' swap file on your hard drive.

The tests were made using three ReadyBoost-capable drives: Kingston's 1GB DataTraveler ReadyFlash, Lexar Media's 4GB JumpDrive Lightning, and Ritek's Ridata 1GB Twister EZ Drive. The results, however, showed little or no improvement, and in some cases it even caused Vista to slow down.

First, we used our WorldBench 6 Beta 2 benchmarking suite to test whether any of these devices sped up general Windows use when plugged into a desktop PC (an HP Compaq dc5750) and a notebook PC (an HP Pavilion tx1000). They didn't. At best, the Ridata had no impact on the notebook's WorldBench score. At worst, the Lexar slowed the desktop's WorldBench score from 42 to 39.
An area that did show some speed improvement - almost unnoticeable though - is application load times. Head over to the article to see the details and the data chart with the benchmark results.