Case fan speed

[FlutterGuy]

Hi,

I've got a 140mm case fan and it's too loud. It's plugged into the motherboard by a 3 pin connector, so there ought to be a way of controlling it using software. SpeedFan recognises it, and knows how fast it's spinning, but I can't for the life of me figure out how to use SpeedFan to slow it down. Does anyone know how to do this, or know of any other ways to do it?

Thanks

 

[Paperdoc]

Some mobo's allow you to configure the speeds of fans connected to the mobo via settings in BIOS Setup. However, watch a fine detail - on some, not all SYS_FAN outputs are speed-controlled - sometimes only the first of two. Some systems, however, do not do this in BIOS. Instead the mobo maker supplies a utility on the CD of drivers, etc that came with it. The utility runs under Windows as an app and allows you to monitor and configure fans that way. So check your mobo manual for how yours is done.

 

[FlutterGuy]

If only it were that easy. The BIOS sees the fan, and can tell me how fast it's spinning, but only gives me the options to display the speed or ignore it. There are two Windows utilities on the motherboard driver disc that let me view the speed, but neither of them give me the option to change it.

If it helps, the fan is plugged into the PWR_FAN socket on an Asus M4A87TD motherboard.

 

[das_stig]

Plugging in a 3-pin fan into a 4 pin pwm socket the fan controller won't work, it will just run at full speed.

I would get a cheap fan controller and control all the fans that way.

 

[ET900]

there is asus software called q-fan, or at least that what it was called on all my asus boards. it should be on download section for your board on their website. however i do warn you of 2 things i hate about asus:

1. their website is badly organised when it comes to drivers. you'll often not see much drivers and software listed for your motherboard but they will usually email you or link you to what you're looking for.

2. ive always found asus motherboard software to be buggy, especially q-fan lol.

still have a look on their support site though!


i would have to go with what the other guy said about about a fan controller though. they're so cheap to buy and it gives you full control over the fans. i understand you may prefer to have the motherboard regulate the fan speed though. its your choice...

 

[Paperdoc]

das_stig said, "Plugging in a 3-pin fan into a 4 pin pwm socket the fan controller won't work, it will just run at full speed." I'll disagree PARTLY and add another thought.

das_stig is quite correct IF the 4-pin output port only acts as a 4-pin fan supply. However, there are two other possibilities that MIGHT be built into your mobo's chipset and BIOS. SOME BIOS's allow you to specify whether you have plugged in a 3-pin or 4-pin fan on a particular port, and change their control mode appropriately so that it CAN control the speed of the 3-pin fan. There also are some that automate this process by detecting which fan type is connected and making their own change.

However, you have your fan plugged into the PWR_FAN port. The original intent of this port is NOT to power or to control any fan! It has a "normal" 3-pin connector, but its only function originally was to accept a connector from the PSU that passes to the mobo the speed signal generated by the PSU's internal fan. (Some PSU's do not even have such a connector, so you can't use the mobo port for this purpose.) In this way your system can monitor the speed of the PSU fan, but it does NOT control it. Some PSU's have their own internal fan speed control system, but it is not done by the mobo.

Now, many mobo's apparently do have the Ground and +12 VDC supplies on the other two pins of this connector, so that IF you plug in any fan other than the PSU special connection, the fan WILL run. But it can only run at full speed, since there is no control of that voltage - the port was never designed to power and control a fan. For THAT reason, your fan's speed cannot be controlled when it is plugged into this mobo port. I am not surprised to hear that neither your BIOS nor the ASUS utilities allow you any control this way.

By the way, I have never heard of a 4-pin PWR_FAN port. For the original design purpose there is NO need for 4 pins which included the PWM signal, because the port was not designed to control a fan speed. Even if you plug a 4-pin fan into it, that connector from the fan will still fit onto a 3-pin port on the mobo, but it will NOT have any speed control possible - it will run full speed all the time.

 

[FlutterGuy]

Thanks for the replies.

Message understood, it won't work. I'm just gonna rewire the 4-pin connector, have it run at 5 or 7 V straight off the PSU.