Question Case fan question

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Maybe.

More information needed:

Full system hardware specs and OS information.

Motherboard, CPU, GPU, RAM?

PSU?

Disk drive(s)?

Fans?

Case?

The answer is likely in the documentation.

Especially for proprietary devices and connections.

Pin by pin.
 
Ralston18 said:
Maybe.

More information needed:

Full system hardware specs and OS information.

Motherboard, CPU, GPU, RAM?

PSU?

Disk drive(s)?

Fans?

Case?

The answer is likely in the documentation.

Especially for proprietary devices and connections.

Pin by pin.
Click to expand...
Motherboard: P35-DS3 rev 2.1
CPU: IntelCore 2 Duo E6750 @2.66 GHz
RAM: Kingston 2x1 GB 400 MHz DDR2, PQI CORP 2X1 GB 300 MHz DDR2
PSU: Antec 350X 350Q
Disk drives: ADATA SU650, SAMSUNG 870 EVO, SEAGATE BARRACUDA 256GB
Fans: Noctua NF-P12 REDUX 1700 PWM
Case: I think DELUX MidTower ATX case
 
This PSU?

Antec 350X PSU

Even if physically connectable (adapters or not) via a 4 pin or 3 pin connection without PWM that PSU may not be capable of supporting the system's power requirements.

Which will lead to another set of problems that may not end well.

The base concern being what/why there is a 4 or 3 pin mismatch?

This motherboard:

Motherboard link

What internal connectors and fan connectors/headers are being used (reference physically numbered Pages 22 & 24)?

How are you trying to match fans to headers?
 
Ralston18 said:
This PSU?

Antec 350X PSU

Even if physically connectable (adapters or not) via a 4 pin or 3 pin connection without PWM that PSU may not be capable of supporting the system's power requirements.

Which will lead to another set of problems that may not end well.

The base concern being what/why there is a 4 or 3 pin mismatch?

This motherboard:

Motherboard link

What internal connectors and fan connectors/headers are being used (reference physically numbered Pages 22 & 24)?

How are you trying to match fans to headers?
Click to expand...
I am using CPU_FAN, SYS_FAN1 and 2 are not being used. PWR_FAN is not being used too. Trying to match fans to headers by the cable of the fan to the port on the 4 pin SYS_FAN1 and leaving the PWM for SYS_FAN2
 
Ralston18 said:
This PSU?

Antec 350X PSU

Even if physically connectable (adapters or not) via a 4 pin or 3 pin connection without PWM that PSU may not be capable of supporting the system's power requirements.

Which will lead to another set of problems that may not end well.

The base concern being what/why there is a 4 or 3 pin mismatch?

This motherboard:

Motherboard link

What internal connectors and fan connectors/headers are being used (reference physically numbered Pages 22 & 24)?

How are you trying to match fans to headers?
Click to expand...
Mismatch I don't clearly know yet
 
Are you able to sketch out and post a connection diagram down to the pin to pin detail level?

Scan or photograph your diagram and post the image here via imgur (www.imgur.com).

The objective being to show the existing connections so anyone following this post can get a sense of the "big picture".

And may spot some error of omission or commision in the connection paths.
 
Ralston18 said:
Are you able to sketch out and post a connection diagram down to the pin to pin detail level?

Scan or photograph your diagram and post the image here via imgur (www.imgur.com).

The objective being to show the existing connections so anyone following this post can get a sense of the "big picture".

And may spot some error of omission or commision in the connection paths.
Click to expand...
Nevermind, I cancelled the order on my Case fans. I have nowhere to mount them. So nevermind.
 
I see OP does not need this, but I'm posting anyway because some info above I consider faulty, and other users of old mobos may need the info.

First, the headers on OP's mobo. From its manual I see that CPU_FAN and SYS_FAN2 both have 4 pins, and SYS_FAN1 and PWR_FAN have only 3 pins. The labels say that CPU_FAN can operate only as a true 4-pin header using the PWM system of fan speed control. On the other hand the SYS_FAN2 header also with 4 pins can operate only as an older 3-pin fan header - that is it does not send out any PWM signal on Pin #4, and it varies the Voltage supplied on Pin #2 to change fan speed. SYS_FAN1 is a classic 3-pin Voltage Control Mode header.

The PWR_FAN header is a special case. These were on many mobos in the early 2000's and the original intent was ONLY as a means of allowing the fan in the PSU to send its speed signal to the mobo so it could be measured and displayed for the user and monitored for failure. It did NOT supply power to that fan - that system had the PSU manage its own fan's speed by itself. But the design had a small wire from the PSU ending in a normal 3-pin female fan connector to plug into the PWR_FAN header. If your PSU did not have such a wire, the intent was you would not use this header for anything. However, MANY mobo makers (like OP's) did connect Ground and +12 VDC power sources to pins 1 and 2 of that header so that you COULD plug into that any fan and it would work. You just had NO ability to reduce the Voltage on Pin #2, so the fan always ran full speed.

When 4-pin fans were introduced into the market their design particularly made them as similar as possible to 3-pin fans so that it was easy to introduce them. So the physical details of the connectors and the assignment of eletrical signals on pins are almost identical. In a 3-pin system the pins are:
#1 - Ground (Black);
#2 - +VDC power (Red), varying from 12 VDC for full speed down to about 5 VDC for min speed without stalling;
#3 - Speed signal (Yellow) consisting of pulses +5 VDC amplitude, 2 per revolution, generated in the fan and sent back on this line to the header for counting and monitoring for failure.

In the 4-pin new system Pins 1 and 3 are unchanged. Pin #2 has a
constant +12 VDC power supply, rather than varying. Pin #4 is added to supply the PWM signal. Inside a 4-pin fan there is a small chip that uses this to modify the flow of current from the 12 VDC fixed supply from Pin #2 through the motor windings to reduce its speed. Colour coding of the wires is different from the 3-pin system.

The result is that you CAN plug any 3-pin or 4-pin female fan connector into any 3-pin or 4-pin male mobo fan header and that fan WILL work. This really minimizes market resistance. But what happens if you mis-match fan type and header type? Plug a 3-pin fan into a 4-pin header and that fan gets +12 VDC power always from Pin #2. It does not receive the PWM signal from Pin #4, and it has no special chip so it could not use that signal anyway. It always runs full speed, so you get lots of cooling but no control. Plug a 4-pin fan into a 3-pin header and it receives no PWM signal from Pin #4 so its chip cannot modify current flow. But it receives from Pin #2 a VARYING Voltage power supply so its speed IS controlled by the header.

To OP's question specifically, then. Yes, you can plug any 4-pin fan into any of your hearders. For your specific headers, according to the mobo manual that 4-pin fan's speed WILL be under control by the CPU_FAN, SYS_FAN1, or SYS_FAN2 header. The PWR_FAN header cannot control the speed of any fan, so the fan will run at full speed always.
 
Last edited:
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Paperdoc said:
I see OP does not need this, but I'm posting anyway because some info above I consider faulty, and other users of old mobos may need the info.

First, the headers on OP's mobo. From its manual I see that CPU_FAN and SYS_FAN2 both have 4 pins, and SYS_FAN1 and PWR_FAN have only 3 pins. The labels say that CPU_FAN can operate only as a true 4-pin header using the PWM system of fan speed control. On the other hand the SYS_FAN2 header also with 4 pins can operate only as an older 3-pin fan header - that is it does not send out any PWM signal on Pin #4, and it varies the Voltage supplied on Pin #2 to change fan speed. SYS_FAN1 is a classic 3-pin Voltage Control Mode header.

The PWR_FAN header is a special case. These were on many mobos in the early 2000's and the original intent was ONLY as a means of allowing the fan in the PSU to send its speed signal to the mobo so it could be measured and displayed for the user and monitored for failure. It did NOT supply power to that fan - that system had the PSU manage its own fan's speed by itself. But the design had a small wire from the PSU ending in a normal 3-pin female fan connector to plug into the PWR_FAN header. If your PSU did not have such a wire, the intent was you would not use this header for anything. However, MANY mobo makers (like OP's) did connect Ground and +12 VDC power sources to pins 1 and 2 of that header so that you COULD plug into that any fan and it would work. You just had NO ability to reduce the Voltage on Pin #2, so the fan always ran full speed.

When 4-pin fans were introduced into the market their design particularly made them as similar as possible to 3-pin fans so that it was easy to introduce them. So the physical details of the connectors and the assignment of eletrical signals on pins are almost identical. In a 3-pin system the pins are:
#1 - Ground (Black);
#2 - +VDC power (Red), varying from 12 VDC for full speed down to about 5 VDC for min speed without stalling;
#3 - Speed signal (Yellow) consisting of pulses +5 VDC amplitude, 2 per revolution, generated in the fan and sent back on this line to the header for counting and monitoring for failure.

In the 4-pin new system Pins 1 and 3 are unchanged. Pin #2 has a
constant +12 VDC power supply, rather than varying. Pin #4 is added to supply the PWM signal. Inside a 4-pin fan there is a small chip that uses this to modify the flow of current from the 12 VDC fixed supply from Pin #2 through the motor windings to reduce its speed. Colour coding of the wires is different from the 3-pin system.

The result is that you CAN plug any 3-pin or 4-pin female fan connector into any 3-pin or 4-pin male mobo fan header and that fan WILL work. This really minimizes market resistance. But what happens if you mis-match fan type and header type? Plug a 3-pin fan into a 4-pin header and that fan gets +12 VDC power always from Pin #2. It does not receive the PWM signal from Pin #4, and it has no special chip so it could not use that signal anyway. It always runs full speed, so you get lots of cooling but no control. Plug a 4-pin fan into a 3-pin header and it receives no PWM signal from Pin #4 so its chip cannot modify current flow. But it receives from Pin #2 a VARYING Voltage power supply so its speed IS controlled by the header.

To OP's question specifically, then. Yes, you can plug any 4-pin fan into any of your hearders. For your specific headers, according to the mobo manual that 4-pin fan's speed WILL be under control by the CPU_FAN, SYS_FAN1, or SYS_FAN2 header. The PWR_FAN header cannot control the speed of any fan, so the fan will run at full speed always.
Click to expand...
Nevermind, I cancelled the order on the case fans. They can't fit into my case. But thank You for this info, I will need it!
 
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