Joe Perez

iTrader: (8)

Well there's your problem.

If the fans only have 3 pins, then the motherboard cannot control their speed.

3 pin fans report their speed to the controller, but operate at 100% all the time. In other words, it's kinda BS. But your fans are operating exactly as designed- full speed all the time. The motherboard has no say in the matter.

4 pin fans report their speed and can also be controlled; a proper closed-loop system. These can be controlled from full-stop all the way to full-tilt-boogie by the motherboard, depending upon demand. The front fan in my media-center PC, for instance, is usually sitting at a dead stop. This doesn't mean it's broken, merely that it's not needed. (The load on that machine is fairly low except for when I've got an emulator fired up on it.)




200ma? 400ma? Child's play. This is utterly trivial and insignificant. Even the shittiest motherboard can easily supply 400ma to a fan. You're inventing problems that don't exist here.

Joe Perez

iTrader: (8)

You are *WAAAAAY* over-thinking this. The problem that Leafy is trying to solve literally does not exist.

At some point, it's necessary to stop coming up with clever solutions, and just say "No, dude, you're being a ******* retard. Read the spec sheets, and maybe you'll understand why what you're asking is total BS."

Full_Tilt_Boogie

iTrader: (1)

I feel ya

I have x2 200mm fans and a 120mm fan running off my mobo.

Leafy

iTrader: (1)

So this is your round about way of saying I need different fans. Why cant the mobo just control the fan speeds open loop? Thats what my nifty ricer fan controller does.

Tw34k

Because they are most likely brushless and reducing controller voltage doesn't properly adjust RPM.

Think of most 3 wire fans as having a failure indicator rather than speed reporting for RPM control.

Full_Tilt_Boogie

iTrader: (1)

I fixed up an old keyboard that had never been cleaned. It was hella gross under the keys.



Ill post the before pics later, and my ghetto agitator I built to clean the keys.

Braineack

iTrader: (62)

did you need your phone to remember where the keys went?

Joe Perez

iTrader: (8)

^ This.

Pretty much every PC fan for the last 20+ years has been of a brushless DC design. Compared to a brushed motor (as used in most automotive applications), BLDC motors are highly efficient and extremely long-lived. However, you cannot control their speed by externally modulating this supply voltage.

BLDC motors contains a teeny tiny little microprocessor which controls a switching inverter to actually make the fan turn. This controller seeks a certain RPM setpoint at all times.

In a 3-wire fan, the 3rd wire is simply a tacho signal, by which the fan reports RPM to the motherboard. This is mostly used to detect the failure of a fan.

In a 4-wire fan, the 4th wire is a control signal which the motherboard sends to the controller inside the fan, to adjust the RPM setpoint.


Further reading:

http://electronics.howstuffworks.com...less-motor.htm

http://en.wikipedia.org/wiki/Brushle...electric_motor

duffbuster243

iTrader: (1)

That does not appear to be a stock AMD cooler. The cooler that came with my Phenom II was a nice 4 pin PWM fan. Either way there should be options for fan control in the bios. The hyper 212 is a nice piece though as long as it will fit into your case, it's quite tall.

Braineack

iTrader: (62)

That's what came in the sealed AMD CPU box. Looking at other's builds with the same CPU, they look the same.

Even when it's running on a low-speed it's still retarded loud. It was so loud my wife in the next room was like WTF is going on? did you break it already?

Should fit, I'm just going to stop by microcenter on the way home and pick one up. I cant wait to ship.

Leafy

iTrader: (1)

The hyper212 should fit in any mid tower case. Now the tuniq tower that I had on my amd, thats a bit of a squeeze in some cases, and doesnt cool any better than the hyper.

Joe, so I'm being a dick to my brushless fans by providing them with some sort of speed control externally? I do think with some creative wiring I could make these fans controlled by the mobo, since they do have their own external controller option on a separate pair of wires.

Joe Perez

iTrader: (8)

The one Brainey has is a stock AMD cooler, and it does have a 4-wire connector.




In the 3 v. 4 debate, I was addressing Leafy, who was talking about his own machine. (The one in which he was afraid the mobo couldn't source a few hundred ma to drive the fan, from the port designed specifically for the purpose of driving a fan.)


In Brainey's case, the fan is loud because AMD are a bunch of cheap-asses who stuck a cheap, undersized fan on a tiny little heatpipe cooler.

duffbuster243

iTrader: (1)

HA, Sounds exactly like what my fiancée would be yelling from the next room. Such little faith in us .

Joe Perez

iTrader: (8)

Good luck, let us know how it goes.

Erat

iTrader: (5)

I'm not sure what this fan debate BS is all about.

I control my case fans with a "remote" fan speed controller.
Not sure how it works, but it does. And it has for years, at least 8 years.

Braineack

iTrader: (62)

i plug my fan in and something controls it.

Joe Perez

iTrader: (8)

It is possible to throttle down 3 pin fans by limiting the current to them to the point where they start to operate in the "slip" region, sort of like how AC induction motors are throttled. This is how most of the older external fan controllers work. It gets the job done, down to the region at which the fan itself simply shuts off.

This is not how OEM designs implement fan control. They output a pwm control signal on the 4th wire, and the fan controller responds by scaling its RPM target to the control signal DC%. In this manner, RPM can be linearly scaled from 0% to 100%.


TL;DR: On method is an open-loop hack, the other is how OEMs do it.

Leafy

iTrader: (1)

That would explain why my fans need to be above 40% or they just turn off.

Braineack

iTrader: (62)

Would you install the EVO so the fan blows upward out the top of the case? or towards the rear and through the rear case fan I have installed?

Full_Tilt_Boogie

iTrader: (1)

Yeah, it was hard to remember the order of the function keys

Mine is blowing out the back.
I think the only reason people put it the other way is for clearance on certain setups.