U3 drives are generally stated not to be compatible with Vista because the preinstalled and optional software won't work. However, you can still use the drive itself for data storage, ignoring the software benefits that usually lead to a higher cost. In addition, some drives are labeled as 'Vista ready,' 'designed for Vista,' or 'includes Vista ReadyBoost.' That can be somewhat deceiving, as any flash drive will work with Vista, and ReadyBoost is a part of Vista, not a technology bundled with the flash drive. The difference is that those drives are guaranteed to offer the best performance when using it as a ReadyBoost drive, though how much benefit it offers is debatable. Thus, I'd just shop for the best deal without being concerned about a 'Vista certification.'
Hope this helps,
I want to buy a flash drive for my WinXp computer , but I want to make sure it can also be used on a PC running Vista. I understand that U3 smart will not work with Vista , but what about an ordinary flash drive like Kingston Data Traveler 1 GB USB Flash Drive for example?