A newbie question on Fans.

[theplanb]

i don't know much about fans..
I'm in the market for 80mm case fans..
What's the difference between 2 wire and3 wire s?
What are RPM monitoring and temperature control?
Is 4 pin molex connector better than 3pin or 2 pins?
Is there an advantage to connect fans on the PSU rather than motherboard?
Are the 4pin connectors for fans on PSU same as the ones you use for hard drives?
How long sleeve bearings fans last? Do they really fail that often?

 

[mechBgon]

80mm case fans usually are found with two types of connectors: 3-pin looks like the one in this picture and 4-pin looks like the one in this picture.

3-pin fans use one pin for +12 volt power, one pin for ground, and may use the third pin to send a revolutions-per-minute (RPM) signal. They are designed to be able to plug into the motherboard, and can also be powered directly from your power supply using a 3-pin -> 4-pin adapter.

4-pin fans don't usually have an RPM wire and are designed to plug directly into the power supply.

RPM monitoring can be useful if you want to make sure you haven't had a fan failure. Temperature-controlled fans are not very common on the market but there are a few including some Nidecs (hard to find) and Enermax ones. They use a "thermistor" to sense the temperature and adjust their speed/airflow accordingly. I also saw a nifty one listed at Plycon that has a little manual adjuster... http://www.plycon.com/enermaxad80.htm

The advantage of powering the fan off the PSU is that it doesn't draw power from the motherboard, which might be a factor with older mobos and/or very-high-current fans... I had a motherboard that had two fan headers fail, maybe from overload? Not sure...

The 4-pin connectors are fully compatible with your hard drives and that's why you see them with a male and female end... it's so you don't give up any connectors.

Sleeve bearing fans aren't necessarily bad. They may run more quietly than their ball-bearing equivalent model, and some are built to last a long time (such as the Panasonic Panaflo series, which use a fluid-bath sleeve bearing).

By the way, 2-wire fans may use either 3-pin or 4-pin connectors, so make sure what connector style you're looking at.

 

[theplanb]

Wow thanks!!
I think I know everything I need now