This is one of the things that made people hate Vista. By default it was set to preload things into RAM in the background, gobbling up memory and potentially slowing the system down, both during the preload procedure and if you happened to want to run a program that the preload procedure didn't account for.
Windows 7 was so good because it was Vista without (much of) the bullshit.
At the end, my windows 7 machine would take an hour to boot if I remember right because Windows used 100% of my hard drive to do god knows what. Windows 7 at the end was literally unusable without an ssd.
Windows 7 was so good because it was Vista without (much of) the bullshit.