4 Pin Fans (PWM) - 1 Pin For Fan Speed?

As far as im aware one of the pins is used for it yes.

Cause the Xeon heatsinks that ship with the chips at work have them normally. But which cable it is I could physically tell you currently.... =/
 
"The system board 3-pin header uses two pins, one each to supply +12V (power) and GND (ground). The fan uses the third pin to transmit fan-speed information to system boards that support fan-speed detection."

That's off the intel site...If it's of any help I dont know. Surely it will be the same coloured cable as on standard 3-pin fans?
 
On my board, the header will allow you to connect a 3-pin fan. This works the same as a normal 3-pin fan header, with +12v, GND, and fan speed detection. The fourth pin is for PWM control of the fan speed. I have my water pump connected to this header and it shows the rpm (I believe it's pin 3).
 
On the 4pins like Artic Cooling Freezer that I use for customers builds I find I cant stop fan with Speedfan, only slow it down, on my own rig with 3pins I can stop it dead (0% to 100% in 5% stages), so the extra pin probabnly gived it 5v constant, so it will run slower if needed.
 
Motherboard header:

 || o | GND (typically Black)
|| o | +12v (typically Red)
|| o | Fan Speed (typically Yellow)
| o | Fan PWM

The top three pins are the normal 3-pin motherboard header.
Usually +12v is yellow and +5v is red, but this doesn't seem to apply to fan cables.

Jokester, I have a Swiftech MCP350, and it has a single blue wire to connect to pin 3 on the motherboard. I presume your pump is similar?

Helmutcheese (what a name!), the extra pin is for PWM control of the fan speed. Basically, what this does is switch the power to the fan on and off very rapidly. If the fan speed needs to be higher, the fan is 'on' more than it is 'off', and vice versa for a slower fan speed. If I use a standard fan on this header it will only run at 12v, unless I use a program like Speedfan.
 
Jokester said:
Aye that's what I'm trying to do, connect my pump speed monitor to it to save wasting a 3pin socket.

Jokester
Click to expand...
I have the rpm wire from my water pump connected to my Zalman ZM-MFC2 4pin header for giving the waterpump speed read out
Plus it gives an alarm for if the pump don't start or stops working...
 
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