You've most certainly read it on the internet, and you may have even heard other supposedly computer-savvy people suggest that deleting temporary files speeds up your (Windows) computer.
But how does that actually work? Drawing on my limited theoretical knowledge of file systems and disk drives, I cannot understand how deleting temporary files should improve file system performance unless the disk is nearly full. How can a temporary file that just sits there impair performance? Can somebody offer a technical explanation of why deleting temporary files (and cookies, and prefetch files) should or shouldn't have an effect on performance?
Edit: It appears that Microsoft thinks so.