Case Fans - Intake/Exhaust, Electrical, Ventilatio


May 31, 2004
Planning to add 2 front (intake) and 2 rear (exhaust) 80 mm fans to ATX case.
Case optionally allows these extra fans and standardly includes 1 side fan. PC
will potentially house 1 CD-Rom drive, 1 DVD drive, 3 Sata 150 drives, and
(approximately) 500 watt power supply (at rear of case). Based on comments, am
leaning towards Panaflo L1A case fans.

1. Are intake fans typically distinct from exhaust fans, or do the case fans
typically have a switch for configuring for intake or exhaust?

2. How are case fans typically connected electrically: to the mobo; to the
power supply; to the case (somehow)? When would it be appropriate to
connect a case fan to the mobo? How do you determine if the mobo can
connect to the 4 fans?

3. What extra connections (fan regulators) are needed so that fan(s) speed will
automatically react to interior temperature (i.e. fans not loud if interior
not that hot).

4. Based on the electrical connections, what type of connectors are needed?

5. Should I disable/remove the side fan and just go with the (regulated ?) 2
front and 2 rear fans (+ power supply fans and CPU heat sink fan)? Would
the side fan be accomplishing anything?


Former Staff
1.) LOL, fans blow in one direction, you want them to flow in, you point them want them to flow out, you point them out. In other words, flip them over one way or the other to get the direction you need.

2.) Either way, they come with 3 pin (motherboard) or 4 pin (power supply) headers depending on what you order. Most boards don't support 4 fans, so you'll want some 4-pin fans. Those headers usually are pass-through so you can chain them together.
3.) Your guess is as good as mine, why not buy fans that have built-in thermal regulation? Or do like me and use moderate speed fans that cool well enough under all conditions yet produce little noise?

4.) Redundant question, see #2

5.) The side fan ideally would blow at the video card. Decide for yourself if you want it.

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