As with all Windows OS's, the newer version is, in fact, slower than the older version. It has been true from all versions of DOS to Windows Vista itself. The new operating system is meant to take advantage of the newer and faster hardware. You will probably notice a 10%-20% decrease in video performance, at least until SP1 for Vista comes out. Other than that, if you have a modern processor, the OS should run just as smoothly as WinXP. Also, Vista follows the normal rule for recent Windows OS's; "If you give a man a fish, he will eat for a day", though this also applies to Vista; "If you give Vista a lot of RAM, it will use all it can". You have to feed the beast called Vista and the memory-hungry issues if you want anything for good performance.