Asus H81I Plus fan controller

[Inet]

Hi
I intend to buy an Asus H81I Plus motherboard to mount a slim desktop. I wanted to put one or two more fans in the case. But the motherboard only has two fan connectors 4 pin PWM. So, how can I mount more fans in the case? A fan controller? If so, where do I plug the controller, knowing that there is only one connector in addition to the CPU connector?
Thanks

 

[Paperdoc]

Your mobo has only one CHA_FAN 4-pin header, and its manual says it is a real 4-pin header using PWM Mode for control. This means you MUST buy only 4-pin fans. This type of mobo header can NOT control any 3-pin fan - it would only run at full speed all the time. That MIGHT be a problem for you - see below.

There are a couple of simple solutions for you to control several fans from this one header. First, you can use a SPLITTER. Here's one with three output arms, although two arms are widely available.

http://www.newegg.com/Product/Product.aspx?Item=N82E16812423163&cm_re=fan_splitter-_-12-423-163-_-Product

With this you could plug up to three fans into one header, but they all must be of the 4-pin type. Note that, of the three output arms, only one has all four pins. The other two are missing Pin #3. This is because a mobo fan header can only deal with the speed signal from ONE fan, so this splitter simply does not connect the speed signals from two of its fans. The result is that only one fan's speed can be detected and displayed, and the speeds of the other two are ignored. This makes NO difference to control of the fans, and you probably don't need to know those speeds anyway.

If you have more than 3 case fans, you can use a slightly different device, a 4-pin fan HUB. Here's one with four output arms

http://www.newegg.com/Product/Product.aspx?Item=N82E16812423165&cm_re=fan_splitter-_-12-423-165-_-Product

There is a five-arm model, too. What's different about a Hub is that it has an extra arm and connector that plugs directly into a 4-pin Molex power output from the PSU. It gets all the power for its fans from the PSU (the mobo header has a limit on how much power it can supply), but it gets the important PWM signal for fan control from the mobo CHA_FAN header. As before, it sends back to the mobo the speed signal of only ONE of its fans.

Now, the problem I mentioned above is that it sounds like your case comes with one or more fans already, and you want to add a couple. VERY often the fans supplied with a case are of the 3-pin type. As I said, you cannot control the speed of that type of fan from a 4-pin header using PWM Mode. So, if that is your situation, you have three choices:
1. Use those case fans, run them from the header using a Splitter or Hub, and just tolerate the fact that those 3-pin fans run full speed all the time.
2. Replace all the 3-pin fans that come with the case with new 4-pin fans that CAN be controlled this way.
3. Buy a particular Fan Hub, the Phanteks PWM Hub. Like most Hubs it plugs into a PSU power output (I think it may be a SATA output rather than 4-pin Molex) and has one arm with a female 4-pin fan connector that goes to the mobo CHA_FAN header to get the important PWM signal and send back one fan's speed. But UNlike other Hubs, this one uses the PWM signal to create its own group of six 3-pin fan ports that use Voltage Control Mode for its fans, which is exactly what is needed for any 3-pin fans you have. But interestingly, 4-pin fans also can be controlled by this signal system, so you can use any mix of 3- and 4-pin fans on this Hub. The Hub says you can use splitters to connect two fans to each of its ports (it actually comes with two), up to a limit of 11 fans total.

All of these solutions allow you to have all your case fans under automatic speed control by the mobo, based on the actual temperature measured at a sensor in the mobo. Third-party fan controllers that you mount in your case front do NOT do any control like that. They do allow you to set the speed of each fan manually, but that means that YOU are the controller who makes the decision when to speed up or slow down your fans to keep your computer from overheating.

 

[Inet]

Your mobo has only one CHA_FAN 4-pin header, and its manual says it is a real 4-pin header using PWM Mode for control. This means you MUST buy only 4-pin fans. This type of mobo header can NOT control any 3-pin fan - it would only run at full speed all the time. That MIGHT be a problem for you - see below.

There are a couple of simple solutions for you to control several fans from this one header. First, you can use a SPLITTER. Here's one with three output arms, although two arms are widely available.

http://www.newegg.com/Product/Product.aspx?Item=N82E16812423163&cm_re=fan_splitter-_-12-423-163-_-Product

With this you could plug up to three fans into one header, but they all must be of the 4-pin type. Note that, of the three output arms, only one has all four pins. The other two are missing Pin #3. This is because a mobo fan header can only deal with the speed signal from ONE fan, so this splitter simply does not connect the speed signals from two of its fans. The result is that only one fan's speed can be detected and displayed, and the speeds of the other two are ignored. This makes NO difference to control of the fans, and you probably don't need to know those speeds anyway.

If you have more than 3 case fans, you can use a slightly different device, a 4-pin fan HUB. Here's one with four output arms

http://www.newegg.com/Product/Product.aspx?Item=N82E16812423165&cm_re=fan_splitter-_-12-423-165-_-Product

There is a five-arm model, too. What's different about a Hub is that it has an extra arm and connector that plugs directly into a 4-pin Molex power output from the PSU. It gets all the power for its fans from the PSU (the mobo header has a limit on how much power it can supply), but it gets the important PWM signal for fan control from the mobo CHA_FAN header. As before, it sends back to the mobo the speed signal of only ONE of its fans.

Now, the problem I mentioned above is that it sounds like your case comes with one or more fans already, and you want to add a couple. VERY often the fans supplied with a case are of the 3-pin type. As I said, you cannot control the speed of that type of fan from a 4-pin header using PWM Mode. So, if that is your situation, you have three choices:
1. Use those case fans, run them from the header using a Splitter or Hub, and just tolerate the fact that those 3-pin fans run full speed all the time.
2. Replace all the 3-pin fans that come with the case with new 4-pin fans that CAN be controlled this way.
3. Buy a particular Fan Hub, the Phanteks PWM Hub. Like most Hubs it plugs into a PSU power output (I think it may be a SATA output rather than 4-pin Molex) and has one arm with a female 4-pin fan connector that goes to the mobo CHA_FAN header to get the important PWM signal and send back one fan's speed. But UNlike other Hubs, this one uses the PWM signal to create its own group of six 3-pin fan ports that use Voltage Control Mode for its fans, which is exactly what is needed for any 3-pin fans you have. But interestingly, 4-pin fans also can be controlled by this signal system, so you can use any mix of 3- and 4-pin fans on this Hub. The Hub says you can use splitters to connect two fans to each of its ports (it actually comes with two), up to a limit of 11 fans total.

All of these solutions allow you to have all your case fans under automatic speed control by the mobo, based on the actual temperature measured at a sensor in the mobo. Third-party fan controllers that you mount in your case front do NOT do any control like that. They do allow you to set the speed of each fan manually, but that means that YOU are the controller who makes the decision when to speed up or slow down your fans to keep your computer from overheating.

Paperdoc, I confess that I was hoping that was you to answer, because I think you are a expert in this field. You are a true encyclopedia, man.
Thanks for the answer.

For the cases I have two hypotheses:
- Bitfenix Prodigy Mini ITX, which uses two fans on the front, two on the top and one on the rear;
- or I build a case, and in this case perhaps I can not even need so many fans.

I'll buy the fans, so it's not a problem for being 3 or 4 pins.
My Psu is a XFX TS 550w. It has several molex and SATA connections.
I read your answer but I would like to ask you some clarification:
- I think the best solution is to use the PWM Phanteks Hub. I connect the front, the top and the rear fans, and they are all controlled by the PWM signal from the mobo CHA_FAN header. But is it correct, for example, to have the top and the rear fan at the same speed of the front fan?
- when the fans are controlled by CHA_FAN mobo header, can they slow down almost to zero, to reduce noise, such as fan controllers can do?
- would it be a better solution to buy a mobo with more fan headers?
- how do you confirm this mobo is a real 4-pin header? Where in the manual?
Thanks and sorry for so many questions.

 

[Paperdoc]

I see that case comes with one fan (unspecified type) that may not even be pre-installed, so it would be easy, if necessary, to set it aside and install only 4-pin fans. Now to your specific questions.

1. IF you do commit to using only 4-pin fans, there is a marginal technical advantage to using a different Hub. The Phanteks basically converts everything to using the older Voltage Control Mode. A different Hub design that uses only PWM Mode cannot control 3-pin fans; however, if all your fans are 4-pin type, that PWM control system is slightly better, especially at lower fan speeds. Besides, it's cheaper. The Phanteks unit sells for about $20. There are other makers with box-style 4-pin Fan Hubs for about $16. But even better, that Hub I linked to earlier with 4 output arms has no box - just a group of wire arms - and sells for just over $4. So if you have only four 4-pin case fans, that would do the job. Remember, what distinguishes a Hub from a Splitter is the presence of an arm that plugs into a PSU power output to supply all fan power. Remember also that most "normal" Fan Hubs only share the PWM signal to their fans and thus use only PWM Mode which cannot control 3-pin fans; the Phanteks unit is different.)

Actually, fan SPEED is not the focus. The airflow rate in CFM is the point - that is what directly produces heat removal. Of course, most fan specs will only tell you that for the fan at max speed, but air flow will be reduced as the fan slows. IF all your fans are the same, feeding them all a common control signal will result in almost identical speeds and air flows from each. On the other hand, it is likely that, if you choose fans of different diameters, the larger ones will produce slightly more air flow than the smaller ones, given the same control signals. They may not exactly run at the same SPEEDS, but the airflow will follow that trend.

I prefer to arrange fans so that there is slightly more intake capacity for air than exhaust; this results in having a very slight positive pressure inside the case, thus preventing sucking in unfiltered (dirty) air at cracks. BUT that assumes that you will use and clean air filters on the intake fans (at the front, usually). I also acknowledge that an air filter in front of an intake fan actually reduces the flow through it, and by an unpredictable amount. For your situation what I might try is two larger intake fans at the front with filters, then ONE smaller fan each at the top and rear for exhaust, and hope that the larger fan size will offset the small interference of the dust filters so that you do achieve "positive pressure" in the case.

2. When you have all your CHA_FANs under mobo-based automatic control, they will run as slow as they can to still provide enough air flow to keep the mobo temperature sensor at the target temperature. As system workload changes, the fans all will change speed. While it is true that, using a manual Fan Controller, you could make those fans run slower and quieter, that also means that they are NOT providing sufficient cooling to keep the system under control. People too often forget that a super-quiet fan may NOT be giving you enough cooling for the system. Anyway, under automatic control the mobo will reduce the fan speeds as low as practical, and that often is very slow. It will also ensure that they never go so slow that they stall and fail to re-start.

3. Given that you plan on using 4 or 5 case fans in total and are happy to control them as a group using a Hub, you do not need more mobo CHA_FAN headers. The only advantage to that would be the ability to create more than one sub-group of fans, each controlled to a different speed and airflow. But how would you figure out what speeds to use? If you just let all mobo CHA_FAN headers do their thing according to the mobo's default settings and all based on the SAME mobo temperature sensor, then all the headers will command the fans to do exactly the same thing, and there are no customized sub-groups.

4. To find the mobo manual, go to its maker's website:

https://www.asus.com/Motherboards/H81IPLUS/

There, click on the "Support" link at the right edge. On the resulting page, click at the right again on "Manual and Documents", then scroll down to the English version of User's Manual at the bottom. Click on the "Global" link and it will download the manual and open it in Acrobat Reader for you (assuming you have Reader already installed).

In the Table of Contents on p. 3 it shows that Connectors are detailed in Section 1.7 beginning on p. 1-11. Scroliing down from there we find on p. 1-14 the heading "CPU and chassis fan connectors (4-pin CPU_FAN and 4-pin CHA_FAN)". Look closely at the labels on the two connector diagrams. Both of them show that Pin #4 is labelled "CHA FAN PWM". That confirms that these headers both send out a PWM signal to their fans, and not some other form of control system. (Mobos that do not use PWM Mode give Pin #4 some label like "N/A" or "5v", but do not claim they supply a PWM signal.)

 

[Inet]

Thanks for the answer.
Some last questions:
- if the mobo, besides the two CHA_FAN 4-pin header, have another 3-pin header and I want to use it, how do I make the fans connection?
- can I connect an hard drive cooling fan from a pin fan header, or there is another solution?
- what fans do you recommend in this case?
- how much power each fan header can supply?
- do you recommend using a SPLITTER or a Hub? ( I am a little confused and did not understand what do you recommend ).

 

[Paperdoc]

1. If you get a different mobo that has both 4- and 4-pin CHA_FAN headers, the 3-pin header is easy. It ONLY works in Voltage Control Mode that is best suited to 3-pin fans, but can also control 4-pin fans. To connect more than one fan to that header you need a SPLITTER, and not a HUB. The Hub only works with PWM Mode from 4-pin headers. With a Splitter you can connect 3 or 4 fans (see below) to the single 3-pin header. The splitter itself can be either 3- or 4-pin design, both will work. To get four outputs from splitters, usually you buy three splitters of 2 outputs each. Then you plug two of them into the output arms of the third one, making four outputs from this "stack". Then you can also use the 4-pin header(s) to connect more fans.

If this new mobo has both 4- and 3-pin CHA_FAN headers, we need to check very carefully whether the 4-pin one really uses the PWM Mode for control, or whether it operates in Voltage Control Mode. This is important just because only PWM Mode provides a PWM signal on header Pin #4, and that signal is required if you want to use a HUB on it (not required if you're using a Splitter). So post back here exactly which mobo we're talking about so I can help check that detail.

2. Yes, you can mount any standard case cooling fan near your hard drive to cool it. Often the drives are near the case front, so you use that fan as an intake fan blowing over the drive first, and then its air passes on through the case. For that purpose, plugging the fan into a mobo CHA_FAN header is a good idea because then its speed will be under automatic control according to the mobo temperature. Now, the fan also serves a case cooling function, and the hard drive's workload is closely related to the overall system workload, so this makes some sense. The alternative, if you don't want that fan controlled that way, would be to buy a simple adapter that allows you to connect that fan directly to a PSU fixed 12 VDC output from a 4-pin Molex connector. This would have the fan run at full speed all the time to ensure lots of hard drive cooling. Here's one that has an extra Molex female output connector to replace the one you "use up" by plugging the adapter into an output, and it has a single 3-pin fan male output

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=-1&IsNodeId=1&Description=fan%20adapter&bop=And&Order=PRICE&PageSize=36

If your PSU does not have a 4-pin Molex output, this adapter can plug into a PSU's SATA power output and convert it to a Molex female and an extra output for a 3½" floppy drive you do NOT need.

http://www.newegg.com/Product/Product.aspx?Item=N82E16812422644&cm_re=SATA_power_adapter-_-12-422-644-_-Product

3. Which fan for the hard drive? Any standard case ventilation fan will do the job. It does not need to be one rated to "high pressure" - those are for use on CPU finned heatsinks that offer more air flow resistance. If you're going to use it for both drive cooling and case cooling, choose as if it were just another case fan and will fit in the case location you choose near the drive.

4. A standard mobo fan header can supply power up to 12 VDC and at a max of 1 amp. Most modern case fans consume from 0.10 to 0.25 amps, so connecting 3 or 4 to a single fan header using Splitters is OK. Check the specs for the fan you are choosing to see what its max current (amps) rating is. The total amperage load on the header is simply the sum of the amps of all the fans on THAT header. Each header is treated separately. If you are using an unusual fan that consumes a lot more, or if you're connecting many fans to a single header, then you need a Hub instead of a splitter. The Hub gets all the power for its fans from the PSU, thus avoiding the limit of the mobo header. However, ALL Hubs REQUIRE a PWM signal from the header's Pin #4, so you have to check the mobo manual to determine whether or not its fan header is using PWM Mode for control.

5. Whether to use a Splitter or a Hub depends on three factors.
(a) A Hub can ONLY be used if the mobo header it plugs into truly uses PWM Mode, because the PWM signal is required for the HUb to operate. Most Hubs (Phanteks model not this way) can only output power and control in PWM Mode, so they can NOT control any 3-pin fan.
(b) If you have any 3-pin fans, the only way to CONTROL them by a mobo header is if the header uses Voltage Control Mode. (A 3-pin fan on a true 4-pin header that uses PWM Mode can only run at full speed.) SOME mobo 4-pin headers actually operate only in Voltage Control Mode and ignore their 4th pin, so these headers can power and control both fan types; they just cannot be used with a Hub that needs the PWM signal. SOME 4-pin headers offer you a choice in BIOS Setup of which control method is used, so you can control either fan type, but not mixed fan types on the same header. SOME 4-pin headers are only PWM type, so they cannot be used to control 3-pin fans, unless you use the Phanteks Hub to "convert" it to a group of 3-pin output ports.
(c) How may fans do you need to connect you each CHA_FAN header on your mobo? As I said above (Item 4), it is quite OK to connect 4 standard fans to a single header using just a Splitter. Maybe even more, if you check the total amps used by all the fans on that port. If you need to connect more fans on a single header, OR if your fans consume more than "normal" power, then you must use a Hub that gets its fan power from the PSU directly. However, as I said, a HUB MUST have a PWM signal from a real 4-pin header using PWM Mode.

 

[Inet]

Ok, I got it. I asked this question because in the meantime I still have not decided which motherboard I'm going to use, because I have a doubt in the space available in the case, as another post I've already opened.
I think you're a real expert, and if you did not mind, when I went to buy the motherboard I would ask your opinion. Ok?
Thank you very much for the information. You are a true encyclopedia. That's why I love this forum.
Thanks again.

 

[Paperdoc]

Thanks for the Best Solution. Glad to help with more questions later, although I certainly don't know loads of stuff about all mobos.