Great tweak/hack or not ?

Thanks as usual to the MG folk.

I`ve come across a tweak/hack, call it as you wish, concerning IRQ PRIORITY. I`ve gone ahead, on my vista machine, and priotized CMOS and and my video card as 2 and 3. My machine is running MUCH faster. Best tweak I`ve ever come across. Surely their is a downfall somewhere? Is this the holy grail? :-D Any thoughts and comments would be appreciated.