I replaced the cpu fan but can't control the speed anymore

[osak4x]

The original CPU fan was very faulty and I had to replace it.

 

I bought a cooler master sickleflow 120mm and I successfully removed the original CPU fan and replaced it with the new one.

 

The problem I have now is that I can't control the fan anymore. I noticed the fan didn't have the extra pin hole but I didn't think it would be a problem because the other chassis fans only have 3 pins and I can control them just fine. But I can't.

 

I have been using ASUS Fan Xpert 2. I tried changing the RPM settings in the BIOS and I also tested it with SpeedFan program and no luck. The CPU Fan is always running at 100%. Is there a way to control the CPU fan?

 

My motherboard has 2 CPU fan connectors, would be there any difference if I connect it in the other one?

 

Kind of off topic question: If I can't control the CPU fan it will be always running at 2000 rpm. Will that somehow cause any problems with the air flow? Do I have to increase the other fans rpms to match the CPU fan?

Setup > I have 4 fans:

1 front fan 200 mm running at 450 rpm

1 top fan 200 mm running at 450 rpm

1 back fan 120 mm running at 1400 rpm

1 CPU fan 120 mm running at 2000 rpm

 

Thanks in advance.

 

Specs:

Case: HAF 912

CPU Cooler: Hyper Evo 212

Motherboard: Asus P8Z77 V-PRO

[Frankie]

That extra pin hole is for PWM function = speed control. So probably you are out of luck until you buy a new fan with PWM

[KamiKatze]

Regarding your second question: i would rather try to tune down the sickleflow and crank it up once the CPU temps get to high.

 

Now about tuning it down, have you tried tha fan on other fan headers? in order du evaluate whether the fan or the board is the problem?

[osak4x]

That extra pin hole is for PWM function = speed control. So probably you are out of luck until you buy a new fan with PWM

 

I'm a newbie obviously. I thought that didn't matter because all the other fans can be controlled even if they only have 3 pin holes.

[Lotus]

The CPU fan header is set for PWM speed control, which is what that last pin is for. 3-pin fans can still have speed controls, but it must be done via controlling the voltage. I'm not sure if your board supports voltage control over the PWM CPU fan header, but that is what you need to look into.

[Frankie]

I'm a newbie obviously. I thought that didn't matter because all the other fans can be controlled even if they only have 3 pin holes.

 

Hey, nothing wrong about it, we all had to start somewhere

 

@Lotus described it into detail for you

[KamiKatze]

I'm a newbie obviously. I thought that didn't matter because all the other fans can be controlled even if they only have 3 pin holes.

 

Try a different fan header with the fan to see if that helps.

 

Resetting your BIOS could help, allthough you would have to do all the settings again, in case you have performed any. refer to your manual on how to clear the BIOS keyword: clear CMOS

 

You could try flashing a BIOS update. It's easy and mostly not dangerours. 

[osak4x]

Regarding your second question: i would rather try to tune down the sickleflow and crank it up once the CPU temps get to high.

 

Now about tuning it down, have you tried tha fan on other fan headers? in order du evaluate whether the fan or the board is the problem?

 

I would reduce the speed of the cpu fan if I could. And I don't think the cpu fan is faulty or the connector is faulty. I will try switching to the OPT_FAN connector but I don't think that is gonna do something.

[KamiKatze]

I would reduce the speed of the cpu fan if I could. And I don't think the cpu fan is faulty or the connector is faulty. I will try switching to the OPT_FAN connector but I don't think that is gonna do something.

 

try Sys_Fan1 first. or try any connector that you know can control a 3 pin fan.

[osak4x]

Try a different fan header with the fan to see if that helps.

 

Resetting your BIOS could help, allthough you would have to do all the settings again, in case you have performed any. refer to your manual on how to clear the BIOS keyword: clear CMOS

 

You could try flashing a BIOS update. It's easy and mostly not dangerours. 

 

I have had bad luck with this PC so I rather deal with a fan replacement again than resetting my bios.

 

I was thinking about my options. I could connect one of the chassis fans to the power supply and connect the cpu fan to a chassis fan connector. The only problem is that I would get warnings because the motherboard would think there is no cpu fan.

[KamiKatze]

I have had bad luck with this PC so I rather deal with a fan replacement again than resetting my bios.

 

I was thinking about my options. I could connect one of the chassis fans to the power supply and connect the cpu fan to a chassis fan connector. The only problem is that I would get warnings because the motherboard would think there is no cpu fan.

 

I know the warning, had a similar situation before, haha. Just press F1 and skip

 

A newer BIOS could help. But your solution is good too if that other fan is less loud.

 

Edit: you could also just plug your sickleflow to a working header and the fan from that header into your CPU header. That way you won't get the error warning.

[LogicalDrm]

There might be setting in BIOS for changing CPU header from PWM control to voltage control which could solve this problem also.