Mini-ITX case airflow design and Intel's TASC Guide

[jamese]

Hi,

I'm looking for some advice on designing optimum airflow for a small custom mini-itx case I'm trying to build. I've been using Intel's TASC guide as a reference, but there's a few things that are suggested that I'm not too sure about. For example, Intel suggests:

1. Vent right above the CPU (100x130 mm, and no more than 50 mm away)
2. Case fan inline with memory modules

1. Looking at other cases, they seem to be designed primarily to use the case fan to pull cool air *across* the CPU/hotspots from inlet vents not directly above the CPU. The Intel guide seems to suggest the same, but I'm left wondering if having a vent right above the CPU is necessary, or what the pros/cons are? (aesthetics is probably one con to CPU vent on side). One thing I like about the vent right over the CPU is that you don't need any space between the CPU fan and the case.

2. Case fan inline with the memory modules seemed like a good idea, until I noticed that some Mini-ITX motherboard manufacturers put the MB power connector right there. Next best place seems to be further back towards the IO ports. But are two 80 mm fans necessary to cool such a small case, especially if the power connector wires could potentially block the fans airflow. Is even one 80 mm case fan necessary when using a vent right above the CPU???

I've also been wondering about having vents on the bottom of a case. Does anyone have any pros/cons for putting inlet vents on the bottom of the case, instead of on the side. That way airflow would theoretically be pulled through the bottom vent, across the motherboard and out the other side (with case fan), without putting holes in the side cover.

The TASC guide also mentions that the area above the IO ports at the back should be well ventilated. Can you have too many vents for the case fan to pull air through?

http://www.formfactors.org/developer%5C ... e_V1.0.pdf

airflow.png