I'm not shy about my enthusiasm for Windows Vista. I have run it on a wide range of machines - old and new, big and small. I was impressed by Vista's performance on my five year old laptop - the Operating System automatically measured the hardware performance and adjusted it's configuration accordingly to make the best of what was available. The machine in question did have 1Gb of RAM which WAS more than most corporate laptops back in 2003 and this certainly helped Vista.
Microsoft's recent 4th quarter earning report included the statistic that 180 million copies of Windows Vista have been purchased by customers Worldwide.
In my experience it's critical to make sure you have the latest drivers for your hardware devices to ensure optimum performance - the VAST majority of these are available from Windows Update and can easily be accessed by "update driver" as follows:
Type "Device Manager" in the search box at the bottom of the "Start" menu, select the Device Manager from the list then navigate to the "Update driver" menu item as shown below by selecting the device that's not performing as you'd expect and clicking the right mouse button:
Certainly there are some computers that simply don't have sufficient device driver support though thankfully most machines produced in the last three years have full support.