Is this fine?

[aren332]

Lets say I have a 12v 5 amp fan. If I solder the 12v+ and 12v- wires to a molex connector which ill connect to my psu and solder the rpm and pwm wires to a standard 4 pin fan connector which I will connect to the motherboard, can my motherboard header can damaged if only the rpm and pwm wires are connected to it? In other words, if a fan is 12v and 5 amps, then those 5 amps only go through the 12v+ and 12v- wires, not the pwm and rpm wires, right?

[NorKris]

12-   does not exist

 

but yes it will work

[aren332]

2 minutes ago, NorKris said:

12-   does not exist

 

but yes it will work

What do you mean 12- doesnt exist, I meant like the 12v+ and 12v-, the red and black wires

[NorKris]

Just now, aren332 said:

What do you mean 12- doesnt exist, I meant like the 12v+ and 12v-, the red and black wires

red is          5v
Yellow is     12v

black is      ground

[aren332]

4 minutes ago, NorKris said:

red is          5v
Yellow is     12v

black is      ground

yeah i meant 12v- is ground, also will it work if I run the fan at 5v from a rewired molex but keep the pwm and rpm connected to the 12v motherboard header?

[NorKris]

1 minute ago, aren332 said:

yeah i meant 12v- is ground, also will it work if I run the fan at 5v from a rewired molex but keep the pwm and rpm connected to the 12v motherboard header?

u cant connect 12v to 5v. 

and u "cant" run fans on 5v if u want performance

 

connect 12v and ground to  the PSU  (via molex)

connect PWM and RPM signal to motherboard

[aren332]

1 hour ago, NorKris said:

u cant connect 12v to 5v. 

and u "cant" run fans on 5v if u want performance

 

connect 12v and ground to  the PSU  (via molex)

connect PWM and RPM signal to motherboard

i have 2 different fans which molex connectors i modded a little and flipped so that they both get 5 volts instead of 12 so they run quiter. What i mean is that if I do the same here, except connect rpm and pwm to motherboard, will it work?

[NorKris]

21 minutes ago, aren332 said:

i have 2 different fans which molex connectors i modded a little and flipped so that they both get 5 volts instead of 12 so they run quiter. What i mean is that if I do the same here, except connect rpm and pwm to motherboard, will it work?

yes every fan can take the 5v 

 

but here is my problem with the logic:  PWM (the 4th wire) controlls the speed. meaning that u in bios (or software) can tell it to run at "5v-ish" speeds all the time.

Limiting ur self to only 5v when u have PWM makes no sense..

[freeagent]

It depends on the fan really. Some don't like 5v, some don't mind. I have a 92x35mm fan that runs at 1800RPM with only 5v, moves good air. At 12v it is at 3900RPM and ready to blend.