Yay! Vapor liked what I had to say! *parades around the room enthusiastically, with a great sense of intellectual accomplishment.* Finally I am a valued member of this community! ....I hope

I recall seeing pressure measured once by having the fan blow into a small air tight enclosed space, with some kind of atmospheric pressure measuring gauge within the enclosed space. I don't remember where I saw this, it was online years ago.

And I actually disagree with the whole screamer delta fan statement. I've had a 150cfm Delta on the back of my case working as the exaust for about 4 years now, and it does a great job when turned all the way down. It feels like a leaf blower, and yet it barely makes any noise. Of course, I don't have my computer up on the desk out in the open like some people do, but its not tucked down inside a desk either. It just sits down on the ground next to my feet under a table. I never notice it running... ever.