zagood said:
<< Ducting would give you both, just a pain in the butt sometimes. >>
Everyone who's "been here" has seen that contraption with entire arrays of fans replacing whole case panels.
I've experimented with side-panel blow-holes, but it's an idea I try and avoid now.
And the reasons for that are -- first, the noise, which is no longer confined to the front and rear. Second, in some situations extra vents make it more difficult to keep case interior pressure higher. Higher pressure, denser air; denser air, more effective heat transfer.
Ducting IS a PITA, especially when you want access to the motherboard. But I build my ducts to come apart easily, using velcro-tape-patches and "lap-joints" to hold the duct firmly together.
The idea of ducting really works well when you consider "serial augmentation of air-flow." I've seen some people attempt to increase cooling by putting one fan behind another, but this really doesn't work well. Airflow is still going to be about the same.
If you can arrange to have high CFMs of air intake from the front of the case with large, low-noise fans, it will keep the case interior-pressure higher. With a motherboard duct, this air in the case-interior-at-large is drawn in by the CPU fan, and any excess pressure also seeps through the cracks and (hopefully narrow) openings in the duct around the motherboard. The case exhaust fans, on the "out-flow" side of the duct, does the rest of the work.
My memory modules and my graphics card make natural obstructions that become part of the duct, and narrow crevices between these components and the ducting-board draws air over them -- "low-volume, high-airflow."
It has stabilized my case temperatures. The intake fans push air over the hard disks toward the PCI cards in the lower part of the mobo. Additional pressure feed the area around the memory modules. The CPU fan does the rest of the work, and the air is drawn out through the exhaust fans. I let the low-rpm fans of the power-supply work independently -- again served by high interior-case air-pressure.
NOW -- given all that, there are secondary objectives -- to reduce fan rpms to a point where these equilibria and direction of flow are maintained, but with low dBA's or noise. I think the ducting may dismiss the need for "dual intake" or "dual exhaust" fans.
The main thing, is to get a lot of air to move consistently through the case, and to get that air to move in large part through narrow passages over the motherboard and heatsink base.
That way, nobody gonna call me "fan-boi!"
The blow-holes in the top of the case are not really necessary if all the heat is carried off through the duct. If the PSU is in the top of the case, it also gets a good "feed" from interior case pressure, and should not be any warmer than under "more ventilated" solutions. Blow-holes in the top can also be noisy. You might drop a paper-clip or something in there, too.
And I know what some people will say about my slovenly habits. I agree that it's a good rule to avoid putting cups of coffee or plates with snacks on top of your computer case, but I do it occasionally. Another reason I'd just as soon not have a blowhole there.
