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Old 02-12-2013, 09:55 AM   #1 (permalink)
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Default Case Fans to PSU or to motherboard?

Hey guys,

I recently bought the Cooler Master CM 690 II Advanced case (CM 690 II Advanced (USB 3.0 version) - Cooler Master).

Receiving my Asus P8Z77-V LE mobo tomorrow (ASUS P8Z77-V LE Intel Motherboard - Newegg.com)

I've been reading a lot of varying opinions on the matter; some say it's best not to draw more power than needed from the mobo, and to attach the fans to the PSU directly, while others disagree.

I understand that connecting to mobo allows fan speed control while connecting directly to PSU has fans running at full speed all the time.

I'm not sure if I want to be able to control the speed, but I would assume that's a good thing to have, no?

What do you guys think?

My other question is this: mobo has 2 4-pin chassis fan headers and 1 3-pin power fan header.

The case comes with front and top 140mm fans and a rear 120mm fan, all of which are 3-pin. (They're all attached to molex connectors, so I can connect to PSU if I want to).

First, what exactly is the power fan? From what I understood, I can connect a chassis fan to it, but wouldn't offer any speed control...is that right?

Second, why are the chassis headers on the mobo 4-pin while all my fans are 3-pin? Could it be that I can't control the speed? (just guessing here)

Thanks!
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Old 02-12-2013, 11:48 AM   #2 (permalink)
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Default Re: Case Fans to PSU or to motherboard?

4pin fan headers are for PWM fans but you can connect 3 pin fans to those headers as well. They all basically do the same thing, just lower power to reduce RPMs when your system is cool. It honestly doesn't matter which way you go about connecting your fans as either way is perfectly safe. Having your fans connected directly to the PSU ensures maximum power though.
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Old 02-12-2013, 12:14 PM   #3 (permalink)
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Default Re: Case Fans to PSU or to motherboard?

You can manually change your volts coming from the psu by switching around the wires on the molex connector, you can use (depending on the fan) 5volts, 7volts or full speed at 12volts
Get 12V, 7V or 5V for your Fans | silentpcreview.com
I use the 5volt method on those noisy 80mm case fans for older pc's, makes a difference in db and still allows some air flow
If the board has fan terminals, then I would assume that it is designed to power the fans connected to it
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Old 02-12-2013, 07:07 PM   #4 (permalink)
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Default Re: Case Fans to PSU or to motherboard?

Quote:
Originally Posted by Rawan AbuSalman View Post
Hey guys,

I recently bought the Cooler Master CM 690 II Advanced case (CM 690 II Advanced (USB 3.0 version) - Cooler Master).

Receiving my Asus P8Z77-V LE mobo tomorrow (ASUS P8Z77-V LE Intel Motherboard - Newegg.com)

I've been reading a lot of varying opinions on the matter; some say it's best not to draw more power than needed from the mobo, and to attach the fans to the PSU directly, while others disagree.

I understand that connecting to mobo allows fan speed control while connecting directly to PSU has fans running at full speed all the time.

I'm not sure if I want to be able to control the speed, but I would assume that's a good thing to have, no?

What do you guys think?

My other question is this: mobo has 2 4-pin chassis fan headers and 1 3-pin power fan header.

The case comes with front and top 140mm fans and a rear 120mm fan, all of which are 3-pin. (They're all attached to molex connectors, so I can connect to PSU if I want to).

First, what exactly is the power fan? From what I understood, I can connect a chassis fan to it, but wouldn't offer any speed control...is that right?

Second, why are the chassis headers on the mobo 4-pin while all my fans are 3-pin? Could it be that I can't control the speed? (just guessing here)

Thanks!
Is there any disadvantage (other than acoustic) to fans running at full speed all the time? Or is it better if their speed is regulated?

And what about the power fan header? Does that also offer fan speed control?
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-----------------------------------------------------------------------
13" MacBook Air (mid-2012) / 2.0 GHz Core i7 / 256 GB SSD / 8 GB RAM
-----------------------------------------------------------------------
Toshiba Satellite M645 / Intel Core i3 2.53GHz / 4 GB RAM / Win 7 Ultimate X64
-----------------------------------------------------------------------
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Old 02-12-2013, 07:18 PM   #5 (permalink)
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Default Re: Case Fans to PSU or to motherboard?

Fan headers being controlled depends entirely on the motherboard in question and also bios revision.

There is nothing wrong with leaving fans at 100% all the time.
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Old 02-12-2013, 07:28 PM   #6 (permalink)
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Default Re: Case Fans to PSU or to motherboard?

Okay then. Can I just know the difference between the chassis fan headers and and the power fan header?

Thanks
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-----------------------------------------------------------------------
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-----------------------------------------------------------------------
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-----------------------------------------------------------------------
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Old 02-12-2013, 07:30 PM   #7 (permalink)
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Default Re: Case Fans to PSU or to motherboard?

I think it comes down to:
your need for speed= more system heat
vs.
quiet running pc at stock speed


and then there's that medium some strive for, faster pc and running quiet
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Old 02-12-2013, 07:47 PM   #8 (permalink)
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Default Re: Case Fans to PSU or to motherboard?

Quote:
Originally Posted by Rawan AbuSalman View Post
Okay then. Can I just know the difference between the chassis fan headers and and the power fan header?

Thanks
Not sure there is a big difference, especially if you have a separate cpu fan header. There's fan headers with 3 pins and four pins, here's an explanation of that
Motherboard (CPU) 3 Pin Fan Connector - AllPinouts
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Old 02-12-2013, 07:50 PM   #9 (permalink)
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Default Re: Case Fans to PSU or to motherboard?

Quote:
Originally Posted by Rawan AbuSalman View Post
Okay then. Can I just know the difference between the chassis fan headers and and the power fan header?

Thanks
Pretty much already explained it. There is no difference really. PWM connectors are supposed to be for "higher powered" CPU fans but they pretty much all can only give off like 10w or so for any given fan.
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Old 02-13-2013, 11:59 AM   #10 (permalink)
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Default Re: Case Fans to PSU or to motherboard?

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Originally Posted by PP Mguire View Post
Pretty much already explained it. There is no difference really. PWM connectors are supposed to be for "higher powered" CPU fans but they pretty much all can only give off like 10w or so for any given fan.
Cool. One last thing; would power fan header on my board offer fan speed control?

Thanks!
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3.4GHz i5 3570K / Asus P8Z77-V LE / 8 GB RAM / 120 GB SSD / 3 TB HD / 2 TB NAS
AMD Radeon HD 6850 1GB / Cooler Master CM 690 II Advanced / 32" Samsung LCD
-----------------------------------------------------------------------
13" MacBook Air (mid-2012) / 2.0 GHz Core i7 / 256 GB SSD / 8 GB RAM
-----------------------------------------------------------------------
Toshiba Satellite M645 / Intel Core i3 2.53GHz / 4 GB RAM / Win 7 Ultimate X64
-----------------------------------------------------------------------
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