I have one fan header on my mobo that all case fans are running off of. they run to a row of headers that is part of the fractal meshify 2 case. however, 4 of those fans are 140mm and 2 are 120mm ie., different rpms at different percentages. when i look in hwinfo for the chassis fan info i get it in rpms...so how do i know which fans rpms those are? thanks in advance for any help.