How many fans can I connect with my current mobo and psu?

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coohjay

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I currently have a EVGA supernova g2 650w modular power supply, and a M5A78L-M Plus Asus motherboard. Me not knowing much about cables and connectors, I was wondering how many case fans I can have.

I also have the Corsair Carbide SPEC 02, and it has 2 case fans, I also have a cpu cooler but that connects to the cpu fan connector on the motherboard. All together, my case can support 6 case fans, 1 at the rear, 2 at the top, one at the bottom, and 2 at the front.


Question: How many fans can I power using my motherboard and power supply, as I do not look to invest in any fan controllers or fan splitters at the moment. Thanks to anyone who replies!


note: the fans im looking to buy have the 4 pin connector
PSU: http://www.newegg.ca/Product/Product.aspx?Item=N82E16817438054
MOBO: http://www.memoryexpress.com/Products/MX62484
 
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You can daisy chain as many Molex fans together as you see fit. There will be no problem doing this.

Molex was originally created to power old mechanical hard drives, and the platters in those old drives weighed a metric ton (not really). Molex could be daisy chained back then and the standard has remained the same. It woud have no problem powering a few dozen fans daisy chained together if it had to.
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maxalge

maxalge

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Daisy chain them, you can have as many as you want
 
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weberdarren97

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You can daisy chain as many Molex fans together as you see fit. There will be no problem doing this.

Molex was originally created to power old mechanical hard drives, and the platters in those old drives weighed a metric ton (not really). Molex could be daisy chained back then and the standard has remained the same. It woud have no problem powering a few dozen fans daisy chained together if it had to.
 
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coohjay

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What's daisy chain? haha sorry can you explain it to me because I've never heard of it before.
 
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coohjay

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Would it be harmful or damage anything in any way? How would i connect a chain of connectors? The fans are actually 4 pin btw
 
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weberdarren97

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The fans you linked have Molex connectors. Just plug one fan into another until you have one solid chain of Molex connectors, then plug that into the power supply.

Oh wait... You changed the fans you want? Unless you're willing to buy and hook up splitters, Molex would be easier. Standard fans with the fan connectors (not Molex) on them cannot be daisy chained without special connectors and splitters.
 
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Karadjgne

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The best option is still a fan splitter. With pwm fans, all you need is the tach wire and the pwm signal wire. Power comes from molex/Sata connectors, so there's no drain on the motherboard itself but you still have control over the fans speed.

With this option you could easily turn the boards single fan header into 4 fans, using 2 as exhaust and 2 as intake while still leaving the cpu dedicated.

2x2 is enough for most ATX mid tower cases, regardless of how many ports there actually are.

Like this https://www.quietpc.com/gel-pwm-1-4-pwmcable

With direct to pc fans via molex connectors, there's 2x main issues.
1. Limited options, not many decent fans use that connector, so you get a choice of junk.
2. Zero control. With a direct to psu fan, the fan runs full speed all the time. Extremely noisy, especially with high rpm, cheap fans. Basically pointless for most applications.
 
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coohjay

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I've been reading around and is it true that you can connect 4 pin female connector (fan) to a 3 pin male connector? What I read said that the 4th pin is only for PWM, what does this limit?
 
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Karadjgne

Karadjgne

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Everything. Pwm fans run on a constant 12v. The 4th wire is the pwm signal wire and what it does is send a 'pulse'. Pwm fans are in a constant state of on/off, its how their rpm is controlled. For instance, fan spins up to 800rpm, gets turned off for a fraction of a second, slows to 798rpm, turned back on for a fraction of a second, spins up to 800rpm etc in a constant cycle. All at a full 12v. When the fan curve changes rpm because of temp, the fan just spins faster or slower, but still on/off.

Analog (3pin) fans are voltage controlled. They generally work in the 7v to 12v range. Lower the voltage, fan slows down, make voltage 12v, fan max's speed.

So if you stick a pwm fan on a 3pin voltage controlled connection, there's no pwm signal. Some fans will work as analog, most won't as there's no p signal to turn the fan on in the first place. You can also run into problems with the motor, as it's designed for 12v usage and supplying less voltage adds higher amperage to make the fan spin, burning out the motor.

All cpu fans are pwm. Analog cpu_fan headers haven't been used in years. Since the z77 boards came out, all subsequent boards that have 4pin headers have the ability to accept and control 3pin analog fans. The motherboard detects the lack of a pwm signal trace and uses an analog voltage control instead since it's entirely probable that only 1 or 2 headers will be 4pin, and the rest of the system fans will be 3pin on all but the most expensive boards that have all 4pin headers.
 
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