Oh it makes a difference but you need to properly test this. Alot of people have followed bad tweaking advice and disabled prefetching. Try reading the article and doing the test EXACTLY how it says to. No one anywhere can provide testing documentation to prove otherwise.

So why would you want to cripple an applications launch time? The folder is SELF CLEANING and Windows only removes what is not installed. It is for idiots who don't understand prefetching.