Variable Fan Speeds

[RoamDog]

Gonna try my first build. I just ordered the DFI Lanparty Ultra D. Am about to order a Thermalright X-120. Still trying to decide on the fan. Do all fans operate at multiple different discrete speeds (depending on heat I am guessing)?? Or do some fans adjust their speed (and noise which is the biggest concern for me) while others do not??

Total idiot fan question: How does the wiring for these fans work?

 

[lockmac]

All fans have different speeds. Some are slow spinning so that they are less noiser, whilst others go real fast. Some fans that you can buy are thermally controlled, but not many

With the wiring, for fans that have RPM monitoring, there will be 3 wires. For just normal fans that do not monitor the speed of the fan, they just have 2 wires

 

[cyberknight]

no. most fans are rated to go only at one speed. Variable speed fans are thermally controlled fans. There are also manual speed control fans as well.

If you have an Antec TruePower PSU, those fans have FAN ONLY connectors which undervolt a fan (thus spinning slower) and raise the voltage as the PSU heats up.

Fans can have either a 4-pin molex connector, or just a 3-pin motherboard connector, or both. It's quite easy to do a 5V or 7V mod to a 4-pin molex.

 

[RoamDog]

Which thermally controlled fans would be good choices to go with my Thermalright XP-120?? Would like a very quiet 120mm fan (that also moves enough air to not destroy my CPU).
Since noise is my primary concern, I am looking for a thermally controlled fan so that it can slow down and get more quiet when possible.
What actually controls the slow down? Is it the motherboard or is there a thermometer on the fan itself that allows the fan to control itself?

 

[KheeWhee]

I installed a thermaltake 3in1 with 3 blue leds fan. I glued the temp sensor to the bottom of the xp120 as close as possible to the processor (the heatsink base is quite bigger than the processor).
The fan is extremely quiet at idle while rotating at about 1600 rpm. After an hour of games, the fan runs at around 2200 rpm and is a bit noisier, but still very acceptable. In fact, i hear the front case fan louder even if it is running at 1400 rpm the lowest speed.
Plu, the fan looks great trough the side window with its 3 blue leds lit up.

Very happy with the combination.