CPU Smart FAN Mode, should i choose "Auto" or "PWM"?

[AleksiDj73]

Hello everyone, first of all, English is not my mother tongue so i hope you understand what i say. I went to BIOS to check for any Fan settings for my CPU, i checked every section except the last one which was "PC Health Status", i went there and saw the setting "CPU Smart FAN Mode", this setting was set to "Auto" i clicked on it to see for any other options and i saw "Voltage" and "PWM". I did a quick Google search about this setting and people say that "PWM" is better than "Auto", so i did what they said, i changed the setting from "Auto" to "PWM", my question here is, what does it actually do? I mean what are the advantages of using "PWM" than "Auto"? Is it better? Because i'm a bit confused here. Also my CPU Fan is a 4-pin and my motherboard has a 4-pin for the CPU Fan so everything is good with the headers. Thank you

 

 

Specs:

• Motherboard - Gigabyte GA-P55M-UD2
• CPU - Intel Core I5-750 2.80ghz (OC'ed to 3.1GHz)
• Graphics Card - Gigabyte GTX 1050 TI Windforce 4GB (Not OC'ed)
• RAM - Corsair 12GB DDR3 1333mhz
• SSD - Samsung SSD 860 EVO 500GB

[minibois]

3 minutes ago, AleksiDj73 said:

i went there and saw the setting "CPU Smart FAN Mode", this setting was set to "Auto" i clicked on it to see for any other options and i saw "Voltage" and "PWM". I did a quick Google search about this setting and people say that "PWM" is better than "Auto"

Auto = your motherboard chooses one of the two other options

Voltage = DC mode, the voltage of the fan can be edited to decided how fast it goes

PWM = the 4th pin on a fan header, which has a more granular, more smooth control option. A DC curve is usually in 'steps', while with PWM it's more of a curve, allowing for less noticable fan noise increases.

 

So Auto and PWM should both do the same, as you have a 4 pin fan. But it doesn't hurt specifically setting PWM to on.

[Eigenvektor]

3 minutes ago, AleksiDj73 said:

my question here is, what does it actually do? I mean what are the advantages of using "PWM" than "Auto"? Is it better? Because i'm a bit confused here. Also my CPU Fan is a 4-pin and my motherboard has a 4-pin for the CPU Fan so everything is good with the headers. Thank you

"Auto" determines whether it should use "PWM" or "Voltage" automatically, i.e. it should use whatever your fan supports. If you set it to PWM you're forcing it to use PWM, which requires a fan that supports "pulse width modulation".

 

Voltage means you change the voltage to change the fan's RPMs. PWM means you quickly turn the fan on and off to change its RPMs.

 

https://www.ekwb.com/blog/what-is-pwm-and-how-does-it-work/

[Mick Naughty]

If someone says auto is better than pwm prolly doesn’t understand how it works. The board tends to be smarter than the user. I just use my software and do a fan learn and don’t have any issue. Except on my other rig where they are all 3 pin fans. So I use dc and do another fan learn. 

[AleksiDj73]

8 minutes ago, minibois said:

Auto = your motherboard chooses one of the two other options

Voltage = DC mode, the voltage of the fan can be edited to decided how fast it goes

PWM = the 4th pin on a fan header, which has a more granular, more smooth control option. A DC curve is usually in 'steps', while with PWM it's more of a curve, allowing for less noticable fan noise increases.

 

So Auto and PWM should both do the same, as you have a 4 pin fan. But it doesn't hurt specifically setting PWM to on.

OK thank you bud, i should've known that Auto chooses one of the 2 but anyways thanks

[AleksiDj73]

8 minutes ago, Eigenvektor said:

"Auto" determines whether it should use "PWM" or "Voltage" automatically, i.e. it should use whatever your fan supports. If you set it to PWM you're forcing it to use PWM, which requires a fan that supports "pulse width modulation".

 

Voltage means you change the voltage to change the fan's RPMs. PWM means you quickly turn the fan on and off to change its RPMs.

 

https://www.ekwb.com/blog/what-is-pwm-and-how-does-it-work/

Well how did i not think that, that Auto choose between the 2.... I totally forgot about that lol sorry. So choosing Auto or PWM is the same right? it's just leaving behind the Voltage option

[Eigenvektor]

Just now, AleksiDj73 said:

Well how did i not think that, that Auto choose between the 2.... I totally forgot about that lol sorry. So choosing Auto or PWM is the same right? it's just leaving behind the Voltage option

It should be the same, at least I would assume it to prefer PWM in case the fans support it (which yours do). Otherwise it would simply fall back to Voltage.

[AleksiDj73]

Just now, Eigenvektor said:

It should be the same, at least I would assume it to prefer PWM in case the fans support it (which yours do). Otherwise it would simply fall back to Voltage.

OK thank you. Yes true true, but thanks for you help!