Why does typing this into my search make my laptop lightening fast?

[kevo2k7]

About 3 years ago i was browsing about some geeky forum and seen a tip on it to type %SystemRoot%\system32\rundll32.exe advapi32.dll,ProcessIdleTasks into my laptop's Search facility ( Via the start and search, im on vista but it works for Xp aswell) anyway i i recall someone saying it completely clears the history as if you had just powered off and back on the laptop, or something along those line's?
Can anyone in the know, tell me exactly what this does as it only takes like 1 second and completely speeds my laptop up when its starting to get sluggish.
By the way if you haven't tried it then give it a try and you will know what i mean.
Cheers for any description that explains exactly what this does to my laptop!
Kev

[rojash]

http://www.thewindows...2-dllprocessidletasks

[kevo2k7]

Thanks Rojash, that explains it!.