Vista is a power hungry resource eater which can really bog down a computer to a snail pace than compared to previous versions of Windows. Even with the highly innovated functions such as superfetch and ready boost still did not make Windows Vista popular
Windows 7 has been released for awhile now and the general feedback has generally been good. The testimonials have been great people usually stating that the start up and shut down times are quick and this is the reason why some users have made the switch from Vista to Windows 7. Windows 7 shines when it comes to performance of boot up, standby and back to resume, hibernation and back to resume and shutdown, this is where you can see the undisputed benefits of Windows 7.
Performance is not always defined at application performance, but also, the OS plays lead role in the process chain to make an user's everyday needs more pleasant. When it comes to Windows 7 it is a fierce untamed OS when it comes to PC headroom for the sake of performance. If the OS is a tiny bit faster on application performance, but to start-up and shutdown took several minutes, would an user still want to use it
The verdict is if an individual is looking for a fast PC, even if the system is not the top of the line the user still will notice a difference in performance from other versions of Windows. As a user just make sure the computer as enough ram for Windows 7 because insufficient memory will bog down any system running any OS.