On board 4(3)-pin fan controller for all fans

[jseiler08]

Hello,
I have a MSI Z97 PC Mate. On board there are 2x 4pin CPU headers (only using 1 at the moment), 2x 3-pin system fan headers, and 1x 4-pin system fan header.
Upon further reading, I have found that on the 3-pin headers, the 3rd pin is unused, so the other 2 pins are just steady +12v. So naturally, they don't show up in any software.
And the 4-pin header is really only a 3-pin as the 4th pin is also unused, but apparently is does have the ability to adjust voltage per the tach wire and software like MSI Command center, etc. based on the system/CPU temps. (not a PWM header)

So, what I am trying to do is to take this 4-pin (really 3-pin) header, and control the speed for all case fans simultaneously. However, based on the amp rating, I suppose I can only connect 2 fans to this one header, but I need to control 7.

So is there a solution to being able to use the voltage control from the 4(3) pin header to control 7 fans?

I mean is a DIY sense, what type on electrical device will allow me to take adjusted voltage in, to dictate adjusted voltage out? I mean, I am fairly fluent with relays, but those are simply on/off. Is there a device that can take the variably controlled voltage out of the header, and ramp up voltage to the fans from the PSU?

I am also looking into the NZXT Grid V2, but if i can DIY it, i would rather.

Also, I am open to suggestions for other recommended setups, (not necessarily opposed to using the other CPU header, but would rather not) but I really want to try and stay with auto fan control based on system temps. To me this just makes the most sense. I don't want to have to bother with dials, or touchscreens, etc. Also, I suppose I can use a drive bay type controller, but they are usually not USB tied for control, so i am left with relying on the temp sensors that come with it, rather than the actual board dictating temps.

If I have mis-spoke on any facts, please correct me (still learning)

Thanks in advance,

 

[Paperdoc]

You are correct in reading the fan header pinouts, and they do not meet your needs to control seven case fans. By the way, for all fan headers, the speed signal carried from fan motor to mobo header on Pin #3 is NOT actually used for fan control. It does allow the mobo to display the fan speed for you, and MAY (some mobos) be used to detect fan failure. But automatic control by the mobo of fan speed is determined by measured TEMPERATURES, and not anything else. The CPU_FAN header is based on a temp sensor built into the CPU chip itself, and the SYS_FAN1 header control is based on a temp sensor built into the mobo.

I have never seen a device such as you describe (I've looked for them!) that could use the voltage from a header in Voltage Control Mode to produce many voltage-control fan outputs. BUT I know of one fan Hub on the market now that can do the job.

First of all, you do not specify what fan type(s) you have - that is, 3-pin or 4-pin. This is important because one cannot control the speed of 3-pin fans from a PWM header, although it IS possible to control many 4-pin fans using a PWM Hub from one 4-pin header.

But I suppose you have 3-pin fans, and there is one Hub that can do this. It is the Phanteks PWM Hub.

http://www.newegg.com/Product/Product.aspx?Item=N82E16811984004&cm_re=phanteks_pwm_hub-_-11-984-004-_-Product

It draws all power for the fans from the PSU directly using a SATA power output connector. It MUST have access to a true PWM signal from a mobo header operating in PWM Mode, and you have two of those - the two CPU_FAN headers - and you are not using one of them. (As you see, the 4-pin SYS_FAN header is NOT of the PWM type.) This Hub has six 3-pin output connectors, and its manual says you CAN use a Y-splitter on at least five of them to connect two fans to each header - in fact, I believe it comes with two such splitters. So you could connect eight fans to this header out of the box. What makes this particular Hub work for your situation is that it is NOT the same as most PWM hubs. Most merely share the PWM signal and can still control only 4-pin fans. But the Phanteks PWM Hub uses the PWM signal it gets from one mobo CPU_FAN header to create its own group of six 3-pin headers operating in Voltage Control Mode, so it CAN control 3-pin fans. (Actually, because of a backwards compatibility feature of 4-pin fans, it can control those, too, so that any mix of 3-pin and 4-pin fans can be used with this Hub.)

The instructions with the Hub tell you to connect its fan connector to the mobo CPU_FAN header, plug its power connector into a PSU SATA power output, and plug your actual CPU cooling fan into the Hub's Port #1 (white). This is because that port is the only one that will forward the fan's speed signal back to the mobo, and it is important to have the real CPU cooling fan report its speed. However, in your case, you have already connected your CPU fan to the CPU_FAN1 header. So just plug this Hub into the CPU_FAN2 header to pick up a PWM signal. I can't tell from the manual, but IF it shows you separately the speed of the fan on the CPU_FAN2 header, that will be whichever one you connect to the Hub's white Port #1. All the other case fans' speeds simply will not be measured and reported.

Compared to the "ideal" situation, this arrangement has one small factor that is not quite ideal. This system will place all your case ventilation fans (connected to this Hub) under control based on the temperature measured inside the CPU chip, rather than on the temperature measured somewhere on the mobo. However, there is a pretty close relationship between workload (and hence internal heat generation) in the CPU and elsewhere in the mobo system, so this control strategy is quite reasonable. And it DOES give you the automatic temperature-based control of fans that you realize is best for your system.

 

[jseiler08]

Thanks for the reply, I believe this is just what i'm looking for, and only $20!
I read some info on it, as well as a well spelled out explanation of what it does and doesn't do from another forum here. But I do have a few questions to create the best setup.

Statements i believe to be true about the Phanteks PWM hub, please correct me if i'm wrong;
1. It basically accepts the 4-pin PWM connection from CPU_FAN1 header, but then changes it to voltage variable for all fans connected to it, INCLUDING the CPU cooler. So I lose the PWM function for the cooler fan
2. It can accept just a 3-pin voltage variable input, and then "split" it out to multiple fans, with voltage control, as long as the PSU is NOT powering the hub. However, severely limited to current draw. If supplied with a 3-pin input, and also PSU power, then all fans will run at +12v, so it basically becomes a big splitter.
3. I can run my CPU off of CPU_FAN1 header in isolation, taking advantage of the PWM control for the CPU cooler, as well as run the hub with PWM input from CPU_FAN2 header, and still use the functionality of the PWM --> voltage-variable along with the hub, and not fall into the #2 issue above

Does this all seem correct, that going with CPU_FAN2 header would be most appropriate?

Also, what about the 4(3)-pin SYS_FAN1 header? I read somewhere that it could possibly be a switchable header, between PWM and voltage variable...but there is nothing in the bios about it. Also read, it could be auto-sensing...if so, and if it does in fact support PWM when auto-sensed, then do you suppose that would be the best header for the hub, and leave the CPU_FAN2 header for another cpu cooler later?

Sorry so winded, just like to be thorough.

Thanks in advance!

 

[Paperdoc]

1. Yes, this Hub uses a PWM signal from one mobo header to create its own six Voltage Control Mode (aka 3-pin) fan headers. If you plug your CPU cooling fan into the Hub's Port #1, that fan then is NOT using PWM Mode. Now, a PWM fan plugged into a 3-pin header in Voltage Control Mode WILL operate well, and WILL be under control by the mobo. This is part of the backwards compatibility design of 4-pin fans. There ARE a few features of PWM control that are superior to Voltage Control, so doing it this way is not quite as good as using PWM Mode to control a 4-pin fan, but it's OK. HOWEVER, as I said in my earlier post, you don't have to do it that way! You have TWO CPU_FAN headers that BOTH operate in PWM Mode. So you plug your CPU fan into CPU_FAN1 header, and the Hub into the CPU_FAN2 header. Then the real CPU fan DOES run under PWM control (optimal), and the Hub DOES receive a proper PWM signal to work with.

2. You're missing the point about this hub. A big splitter running off a PSU output would supply all fans with a fixed 12 VDC, so they would all run at full speed. The Hub does things differently. It does NOT just split the incoming power to its output connectors. It does something like the mobo does - it uses its own circuits to create six 3-pin headers, ALL of which operate just like a 3-pin header on a mobo with varying voltage supplied to each of its headers on their Pin #2. The difference from the mobo headers is that ALL of the Hub's headers are being governed by the PWM signal the Hub picks up from the mobo, whereas the mobo headers each have their own controller circuits guided by a temperature sensor. In other words, the Hub "converts" one PWM control signal system into six new headers operating in 3-pin mode instead of 4-pin mode.

It is IMPORTANT that this hub's female fan connecto rbe plugged into a 4-pin mobo header that truly does operate in PWM Mode because it MUST have that PWM signal to use for control of its six output headers. If you were to plug the Hub's connector into a 3-pin header operating in Voltage Control Mode, it would NOT get the PWM signal, and the result would be that the hub's outputs all would be frozen at 12 VDC and all its fans would run full speed.

It is important that the Hub get its power directly from a SATA power output connector from the PSU. That is how the Hub can supply up to 30 W (2.5 amps at 12 VDC max) to its fans in total. Mobo fan headers each are limited to no more than 12W max at peak loading. In fact, on the Hub, EACH of its six headers can supply up to about 6 W, but the TOTAL for all connected fans cannot exceed 30 W.

3. Yes that's correct. Use your two CPU_FAN headers separately like that.

There are various ways that mobo SYS_FAN headers have been implemented by the many mobo makers out there. But you read your mobo's manual correctly. This particular mobo does it this way, according to the header descriptions and labels on p. 1-21:

Both CPU_FAN headers are true 4-pin headers operating only in PWM Mode. There does not appear to be any option for these headers to use Voltage Control Mode. These headers can use automatic control by the mobo, and the temperature sensor for this is built into the CPU chip itself. These two headers are the only ones on the mobo that provide a PWM signal on Pin #4.

The 4-pin SYS_FAN1 header is strictly a 3-pin header operating in Voltage Control Mode - there are no other options for it. The 4th pin is not used, even though it is there. The automatic fan control function of this header is guided by a second temperature sensor built into the mobo.

Both the SYS_FAN2 and SYS_FAN3 headers provide NO control of fan speed at all: their Pin #2 has only a fixed 12 VDC on it. Furthermore, neither of these headers uses Pin #3 to acquire the fan's speed signal, so the BIOS cannot display that for you if a fan is connected to either of these headers.

 

[jseiler08]

Thanks again for all your help, and time, and explanations, and recommendations. This is a perfect solution to an issue I didn't even realize would become an issue when I was shopping around for motherboards.
After looking around for quite a bit, it seems there is a lot of confusion around fans and headers. I hope this thread also helps others, as you have explained it perfectly.
Thanks again!

 

[Paperdoc]

You're welcome, and thanks for Best Solution. Enjoy using your system!