Lian Li A10 fan connections and general fan questions

[EffBee]

Please offer help and advice to me on the subject of connecting up fans in a PC case.

(I have created this post in word and pasted it into the forum because it’s a bit long and it took me ages to put it all together)

This issue plagues me whenever I build a new PC or upgrade my old ones. I have never quite got it right. If I am unhappy about case fans then I am sure loads of other casual PC builders are as well, so this post might be of help to more people than just me. In any case the process of just writing this post has helped me.

This post is only about air cooling.


1)SOURCES OF POWER FOR FANS:

1.1) My Motherboard (MSI P965 Platinum):

The Motherboard BIOS is v1.1 (I know v1.2 is available, will load it later):

There are four fan power plugs on the motherboard. I use the word “plug” deliberately. Each plug is a plastic mounting with pins sticking out of the motherboard. They are:

1.1.1) CPUFAN1 (4 Pins) Pins: GND, +12V, Sensor, Control
1.1.1.1) Monitored in BIOS (RPM). I assume this uses the Sensor pin. (Correct?)
1.1.1.2) In the BIOS it is possible to set “CPU Smart Fan Target” between 40 Degrees C and 65 Degrees C . I assume this refers to CPUFAN1. (Correct?) This must refer to the CPU socket temperature and not the CPU internal temperature (Correct?)
1.1.1.3) What is Control?

1.1.2) NBFAN1 (3 Pins) Pins: GND, +12V, Sensor
1.1.2.1) Monitored in BIOS (RPM) I assume this uses the Sensor pin. (Correct?)
1.1.2.2) Took me a long time to figure out what this was. Then found a forum post referring to “NorthBridge Fan” so NBFAN1 is the NorthBridge cooling fan. The only thing is that my motherboard has passive cooling on the NorthBridge. I assume I can plug in any other fan if I want to. (Correct?)

1.1.3) SYSFAN1 (3 Pins) Pins: GND, +12V, Sensor
1.1.3.1) Monitored in BIOS (RPM) I assume this uses the Sensor pin. (Correct?)
1.1.3.2) In the BIOS it is possible to set “System Smart FAN Target” between 20 Degrees C and 45 Degrees C. I assume this refers to SYSFAN1. (Correct) The sensor must be on the motherboard somewhere. (Where?). Default is off.

1.1.4) PWRFAN1 (4 Pins) Pins: GND, NC, +12v, Control
1.1.4.1) What is this for? The power supply doesn’t have anything to plug into this?
1.1.4.2) What is NC and Control

1.1.5) Questions about the four plugs above:
1.1.5.1) What is “Control”?
1.1.5.2) What is “NC” (No Connection possibly)?
1.1.5.3) The motherboard manual says that fans have a red wire which is + (Is it always red on all fans?) and a black wire which is GrouND (Once again always?)
1.1.5.4) In the BIOS it is possible to see the speed at which fans are spinning (RPM) for CPUFAN1, NBFAN1, and SYSFAN1. Looking at the little table above that must be what the “Sensor” pin is for. (Correct?) Do all fans with three wires have speed sensors. If not what else might the third wire be used for ?
1.1.5.5) What does the BIOS actually do to the relevant fan when the temperature is below, at and above the SmartFanTargets? Is it a trigger temperature at which something starts to happen (like a fire alarm going off) or is it a target temperature the BIOS attempts to maintain (like a central heating thermostat). In both cases I’m assuming the only action the BIOS takes is to vary the relevant fan speed? Having thought about it a little while writing this I think the latter case must be true.
1.1.5.6) The four plugs I am discussing are obviously intended to take one fan each. Is it a bad idea to use some kind of Y cable to drive more than one fan from each?
1.1.5.7) Can each plug take any fan of any size. I am not much into electronics but I would guess that bigger fans draw more current. A little NorthBridge fan must be different from a big 6” case fan.
1.1.5.8) Should I just leave a plug on the motherboard empty if I am not using a fan for the intended purpose?
1.1.5.9) Is there any problem using an extension cable with a fan assuming it is intended for the purpose, “straight-through” and the number of pins is the same.


1.2) Power cable from PSU with appropriate converter on end.

1.2.1) For Instance: Cable from PSU terminated by standard molex connector WITH molex to 3 pin adapter.

1.2.2) Specific Questions:
1.2.2.1) How many fans can run off one molex ?
1.2.2.2) Is there any problem ending up with quite a complex web of cables off one Molex, for instance daisy-chained “Y” connectors, lead extensions etc.
1.2.2.3) The cable from the PSU would have two molex connectors on it. Is it wise or problematic to run fans etc off one and peripheral devices like HDD off the other?
1.2.2.4) Presumably running a fan in this way means that only a simple fan can be used. It can only run all time at 12v with no monitoring or speed control etc.


1.3) Fan Controller Unit
Writing this little epic I have pretty much convinced myself that fan controller units are a good idea. I have owned an Akasa unit for several years and its been mounted unused in one of my PCs. I could just never face the hassle of setting it up.

1.3.1) Questions about fan controller units:
1.3.1.1) General advice, things to do, things not to do?
1.3.1.2) Any power problems with large numbers of large case fans?
1.3.1.3) I am nervous about putting my CPU cooler fan into one of these. If I had one I would also worry about the NorthBridge fan. What is the general consensus of opinion – leave it in the motherboard or plug it into the control unit. I see scope for expensive disaster here! The motherboard would have fan failure detection.
1.3.1.4) All those nasty little sensors – where best to put them, how to safely attach them?
1.3.1.5) I assume fan controller units are driven by a molex connector, but if driven by a little 3 or 4 pin fan-type connector – is that really OK?. Those wires are awfully thin?
1.3.1.6) Are they reliable?



2) FANS
2.1) Questions:
2.1.1) When buying a fan for a particular job in a PC system – please provide a checklist of things to consider and get right. What are common mistakes? 2pin? 3pin? 4pin? Male connectors? Female connectors? Different types of fan?
2.1.2) When putting a fan into a system what are things to consider and what are common mistakes? I can think of one – wrong polarity would cause blowing instead of sucking and vice versa.
2.1.3) Are fans ever two pin?
2.1.4) How long should a fan last. When a fan starts to grind/fail/stick/seize does it potentially have the ability to damage anything by drawing too much current?
2.1.5) Is fan speed controlled by reducing voltage only?. I have seen little link wires advertised which drop the fan voltage by a couple of volts I assume to quieten the fan. What do people think of these? I wouldn’t use one on the CPUFAN in any case.

3) MY LIAN-LI A10 CASE FANS
If the questions in the sections above are answered I will be well on the way to having the information I need to work out for myself how to permanently wire up the Top Case Fan, the Rear Case Fan, the Duct Fan in the duct over the expansion slots, the CPU Fan, and the fan in the front driven by Lian-Li’s special 3 way speed control switch.

3.1) Current temporary configuration questions:
CPU Cooler Fan: Connected to CPUFAN1 and working fine
TOP Case Fan (Practically touching CPU Cooler): NBFAN1 – no real reasoning
Rear Case Fan (Near CPU Cooler): SYSFAN1 – seemed sensible
Ducted Fan (Over expansion cards) – The machine still has half its guts hanging out all over the table, but when the build is complete and the ducted fan is replaced it will need power from somewhere not in yet
Front Case Fan – with Lian-Li 3 way switch – not connected yet
Outside of this discussion:
Video card cooling fan ducting air out of case to expansion slot at back of PC – OK
PSU contains two fans one large and one small – seems to be working OK.

3.1.1) The CPU fan is a no brainer and is fine. The wires from the fan on the front with the three way switch are terminated by a plug with three pins inside which needs a socket to receive the three pins. The top, rear and duct fans all have wires terminated by sockets which will receive a three pin plug. Why are they different? Currently I have nowhere to plug the front fan in without buying an adapter. Do any practical experienced people out there have suggestions for a wiring scheme for all these fans?

4) Thank you for reading this far.
4.1) End.

 

[WJA96]

Hi,

For future reference - your post is just too long, too complex and just generally too much. We're here to help, but RTFM isn't a radio station. Many of the questions you have asked are answered in your motherboard manual or are extremely easy to find by using Google.

I started off trying to quote in and out of it, but it's impossible. I will generally try to answer your questions so if I miss anything you may need to ask supplementaries.

Your motherboard is designed on the Intel P965 chipset. The Intel design calls for 4 fan headers called; CPU, PWR, NB and SYS. These are to allow the computer to control the cooling of the processor, power supply, North Bridge and the air inside the computer case. These functions are built-in to the chipset.

These fan headers are required to have minimum specifications. The CPU and PWR fan headers are required to be controlled by Pulse Width Modulation (PWM) and the NB and SYS fan headers are controlled by voltage regulation.

The NB and SYS fan headers have only 3 pins, a +12V pin, a negative or ground pin and an RPM sensor pin. The RPM sensor takes a signal from a sensor on the fan and counts it. The negative connector has to be there to form a power circuit and the 12V pin supplies UP TO +12V. At 12V the fan runs flat out, but the motherboard can vary this down to 5V at which point the fan stops because of how fans work. The fan scales linearly so a fan that spins 1200 rpm at 12V will usually spin at 500 rpm at 5V. In the Intel specification these fan headers are required to be able to supply 600mA at 12V (7.2W). In fact, these fan heades can often supply much more, it depends on what the manufacturer has used in the implementation of the specification.

The CPU and PWR fan headers have 4 pins. They have the same 3 pins as the voltage controlled fan headers but add a fourth pin which is also 12V. The fan header is designed in such a way that a 3-pin fan connector will also fit to ensure backwards compatibility.

If you plug a 4-pin fan connector into the 4-pin fan header then the fourth wire is used to control speed, not the other +12V pin. The fourth pin always has 12V applied to it, but the 12V is turned on and off repeatedly to start and stop the fan very, very fast. This has the effect that the effective speed of the fan can be changed almost infinitely. If you pulse the 12V on once per minute, the fan will spin at 1 rpm, pulse it twice per minute for 2 rpm up to 1200 times per minute for 1200rpm. Once the maximum speed of the fan is reached, the 12V is essentially continuous. The CPU and PWR fan headers are required to have a 1600mA output at 12V (19.2W).

The advantage of PWM is that it gives full control of fan speed over the full rpm range of the fan. This allows fans to run more slowly and more quietly.

The naming of the fan headers is, as you point out, somewhat odd as the power supply and, in your case, the North Bridge have no fans to be powered. That's not Intel's fault, they just designed the specification. It's up to the motherboard manufacturer how they implement it.

In terms of how these things are controlled in the BIOS, generally there is a threshold temperature when the fan is switched on or speeded up and a maximum temperature, when the system is shut down automatically.

The voltage regulated fan headers generally never drop under 5V so below the threshold temperature these spin at 5V then when the threshold is reached they spin up to 12V. If the temperature drops below the threshold, then the fans drop back to 5V.

The PWM fan headers are usually on a programmed curve which has the fans stopped until a threshold is reached and the fan is brought in as necessary. This technique is possible because the chipset, CPU and stock Intel cooler are designed together to keep the CPU working at the top of it's temperature profile while working the fan as little as possible to keep noise to a minimum. Likewise, when the CPU load drops, the CPU itself has it's effective working voltage cut (C1E/Speedstep etc.)

The fan wire colours are basically irrelevant as they will come pre-wired for you. Generally, the +12V should be red, the Negative/Ground should be black, the Sensor should be yellow and the PWM (on a 4-pin header) will be blue or white.

You can't plug them in the wrong way around as the fan headers are keyed. Even if you do, the fans are fitted with diodes to stop them running backwards, so you won't damage them.

Y-connectors should not be plugged into the motherboard headers unless they are properly designed with the sensor cable disconnected. Straight through connectors are fine.

Fans connected to 4-pin molex connectors use only the red 12V cable and black negative or ground cable. They will always run at their maximum 12V speed. There is a modification possible to allow them to run at 7V or 5V off the molex connector, but most of the adapators supplied with fans are 12V. Acoustifan and SilenX supply pre-made 12/7/5V adaptors with their fans.

In terms of how many fans can run off one Molex, it's practically impossible to say, but it depends on your power supply. Generally, you are unlikely to ever reach the limit in normal use. You can plug independent molex connectors into other devices without any concerns.

As regards fan controllers - there are a multitude of types.

The most basic, like your Akasa are simple variable resistors that give 5-12V on a connector and these basically mimic the voltage regulated motherboard connectors. You can also buy PWM fan controllers that mimic the PWM fan headers. Some have temperature control, there are even ones that allow you to mimic the BIOS functions and create complex cooling programmes switching banks of fans in and out. The temperature probes are fundamentally pointless unless you are spending a lot of money (my first PWM fully automated cooling system cost almost £200 for 6 sensors).

As regards the sizes of wires, they generally get thicker the more expensive the product you buy. Obviously they are only designed to carry a few watts so they are never going to be massive, but better manufacturers tend to have better cable quality.

As regards plugging your CPU cooler into one - why would you want do that?

Fan recommendations are not really practical. If I recommend one, someone else will jump in and say they know of a better one. What is definitely true is that many manufacturer's quoted specifications for airflow and noise are somewhat dubious. In my experience, quality control is also extremely slack. One fan may be very, very quiet while another can be quite loud. You pays your money and takes your chances. Pretty much anything you buy from OcUK will be decent. The supplied fans are not a bad compromise between cost (free), airflow (very good) and noise (fine at 5V, quite loud at 12V)

You probably also need to know that the airflow direction is usually indicated on one edge of the fan. Two arrows show the airflow direction and the orientation *** fan spins (clockwise or anti-clockwise).

Fan longevity is effectively as long as you need it for. In normal use you're very unlikely to see a fan die.

All fans are effectively two-pin. 12V and negative. Some big, powerful fans (Thermaltake for example) have a 4-pin molex connector to power the fan and a small, separate, speed sensor lead to plug into a motherboard header so the speed can be monitored.

As regards your case - all Lian Li case fans have a 3-pin fan header and a 4-pin molex connector so you have a multitude of options to plug them into.

The 3-way switch basically does the same as the 5/7/12V adaptors you mention. It works very well and does a good job of silencing the fans in the case. I would be inclined to plug all the case fans into this controller and set it to 5V. If you experience high temperatures (you shouldn't at the moment, but in the high summer you might) then turn it up to 12V and complain about how loud your PC is now.

After going through a whole gamut of fan controllers and spending hundreds of pounds on 'silent' fans I have just turned them all off now. I find the CPU fan is fine for cooling that and the PSU and NVidia graphics card fans are plenty for changing the air in the case. I note NVidia because these draw air from inside the case and expel it outside. ATI fans draw air into the case from outside. I believe this is because the ATI GPU's run so much hotter they need guaranteed cool air.

 

[Snapshot]

1)SOURCES OF POWER FOR FANS:

1.1) My Motherboard (MSI P965 Platinum):

There are four fan power plugs on the motherboard. I use the word “plug” deliberately.
'Header' is the usual term.
Each plug is a plastic mounting with pins sticking out of the motherboard. They are:

1.1.1) CPUFAN1 (4 Pins) Pins: GND, +12V, Sensor, Control
1.1.1.1) Monitored in BIOS (RPM). I assume this uses the Sensor pin. (Correct)
1.1.1.2) In the BIOS it is possible to set “CPU Smart Fan Target” between 40 Degrees C and 65 Degrees C . I assume this refers to CPUFAN1. (Correct) This must refer to the CPU socket temperature and not the CPU internal temperature (Correct)
1.1.1.3) What is Control? This is how the BIOS controls the speed of the fan, using PWM (Pulse Width Modification)
1.1.2) NBFAN1 (3 Pins) Pins: GND, +12V, Sensor
1.1.2.1) Monitored in BIOS (RPM) I assume this uses the Sensor pin. (Correct)
1.1.2.2) Took me a long time to figure out what this was. Then found a forum post referring to “NorthBridge Fan” so NBFAN1 is the NorthBridge cooling fan. The only thing is that my motherboard has passive cooling on the NorthBridge. I assume I can plug in any other fan if I want to. (Correct)

1.1.3) SYSFAN1 (3 Pins) Pins: GND, +12V, Sensor
1.1.3.1) Monitored in BIOS (RPM) I assume this uses the Sensor pin. (Correct)
1.1.3.2) In the BIOS it is possible to set “System Smart FAN Target” between 20 Degrees C and 45 Degrees C. I assume this refers to SYSFAN1. (Correct) The sensor must be on the motherboard somewhere. (Where?). Default is off.

1.1.4) PWRFAN1 (4 Pins) Pins: GND, NC, +12v, Control
1.1.4.1) What is this for? The power supply doesn’t have anything to plug into this? Many current PSUs do have an appropriate connector but normally I'd expect to see a Sensor to make it meaningful.1.1.4.2) What is NC and Control

1.1.5) Questions about the four plugs above:
1.1.5.1) What is “Control”?
1.1.5.2) What is “NC” (No Connection possibly)? Yes
1.1.5.3) The motherboard manual says that fans have a red wire which is + (Is it always red on all fans?) and a black wire which is GrouND (Once again always?) Yes to both, sensor is usually yellow
1.1.5.4) In the BIOS it is possible to see the speed at which fans are spinning (RPM) for CPUFAN1, NBFAN1, and SYSFAN1. Looking at the little table above that must be what the “Sensor” pin is for. (Correct?) Do all fans with three wires have speed sensors. Yes
1.1.5.5) What does the BIOS actually do to the relevant fan when the temperature is below, at and above the SmartFanTargets? Is it a trigger temperature at which something starts to happen (like a fire alarm going off) or is it a target temperature the BIOS attempts to maintain (like a central heating thermostat). In both cases I’m assuming the only action the BIOS takes is to vary the relevant fan speed? Having thought about it a little while writing this I think the latter case must be true. The BIOS will try to keep the temps as low as possible and will gradually increase the fan speeds as the temps rise. It will beep a warning if the set levels are reached.
1.1.5.6) The four plugs I am discussing are obviously intended to take one fan each. Is it a bad idea to use some kind of Y cable to drive more than one fan from each? Yes, as there's a power limit of 500mA per header and I don't know how the BIOS resolves two sensor signals on one header.
1.1.5.7) Can each plug take any fan of any size. I am not much into electronics but I would guess that bigger fans draw more current. A little NorthBridge fan must be different from a big 6” case fan.
1.1.5.8) Should I just leave a plug on the motherboard empty if I am not using a fan for the intended purpose? Definitely!
1.1.5.9) Is there any problem using an extension cable with a fan assuming it is intended for the purpose, “straight-through” and the number of pins is the same. None


1.2) Power cable from PSU with appropriate converter on end.

1.2.1) For Instance: Cable from PSU terminated by standard molex connector WITH molex to 3 pin adapter.

1.2.2) Specific Questions:
1.2.2.1) How many fans can run off one molex ? More than you could want
1.2.2.2) Is there any problem ending up with quite a complex web of cables off one Molex, for instance daisy-chained “Y” connectors, lead extensions etc. No, it just looks messy
1.2.2.3) The cable from the PSU would have two molex connectors on it. Is it wise or problematic to run fans etc off one and peripheral devices like HDD off the other? Peripherals draw more power than fans so it's better to mix them.
1.2.2.4) Presumably running a fan in this way means that only a simple fan can be used. It can only run all time at 12v with no monitoring or speed control etc. No, adapters can be made to run the fan at 7V or 5V, optionally with a flying lead to a mobo header.


2) FANS
2.1) Questions:
2.1.1) When buying a fan for a particular job in a PC system – please provide a checklist of things to consider and get right. What are common mistakes? 2pin? 3pin? 4pin? Male connectors? Female connectors? Different types of fan?
2.1.2) When putting a fan into a system what are things to consider and what are common mistakes? I can think of one – wrong polarity would cause blowing instead of sucking and vice versa.
2.1.3) Are fans ever two pin? Rare these days
2.1.4) How long should a fan last. When a fan starts to grind/fail/stick/seize does it potentially have the ability to damage anything by drawing too much current? No
2.1.5) Is fan speed controlled by reducing voltage only?. I have seen little link wires advertised which drop the fan voltage by a couple of volts I assume to quieten the fan. What do people think of these? I wouldn’t use one on the CPUFAN in any case. They work (I've made my own) but 5V or 7V mods are more popular.

3) MY LIAN-LI A10 CASE FANS
If the questions in the sections above are answered I will be well on the way to having the information I need to work out for myself how to permanently wire up the Top Case Fan, the Rear Case Fan, the Duct Fan in the duct over the expansion slots, the CPU Fan, and the fan in the front driven by Lian-Li’s special 3 way speed control switch.

3.1) Current temporary configuration questions:
CPU Cooler Fan: Connected to CPUFAN1 and working fine
TOP Case Fan (Practically touching CPU Cooler): NBFAN1 – no real reasoning
Rear Case Fan (Near CPU Cooler): SYSFAN1 – seemed sensible
Ducted Fan (Over expansion cards) – The machine still has half its guts hanging out all over the table, but when the build is complete and the ducted fan is replaced it will need power from somewhere not in yet
Front Case Fan – with Lian-Li 3 way switch – not connected yet
3.1.1) The CPU fan is a no brainer and is fine. The wires from the fan on the front with the three way switch are terminated by a plug with three pins inside which needs a socket to receive the three pins. Don't understand this, all the Lian-Li's I've seen terminate the front fan either in a double-ended molex or the standard 3-pin socket. The top, rear and duct fans all have wires terminated by sockets which will receive a three pin plug. Why are they different? Currently I have nowhere to plug the front fan in without buying an adapter. Do any practical experienced people out there have suggestions for a wiring scheme for all these fans?

I hope my additions/changes in red help a bit.

Jonathan

 

[WJA96]

What is “NC” (No Connection possibly)? Yes

If it's no connection then why have a cable there at all? It's the negative.

 

[Noto]

wow @ question

and more wow at answers. All i can say is you guys get medals and im still MIA reading

 

[EffBee]

WJA96:
Thank you very much indeed for your excellent response. That was vastly more effort than I ever expected anyone to make. Sorry my original post was a bit long - I don't tend to use one word when ten will do. (Reaction against txt speak possibly). I will try to keep it simpler and shorter in future. I promise. My mobo manual isn't terribly helpful. It provides technical specs but keeps stopping just short of providing useful practical information. I googled for a while before writing that little epic but I'm so far out of my comfort zone with stuff that I just couldn't get to anything detailed enough. With all the info you supplied I am sure I can now google into more useful areas. Thanks again.

Snapshot:
Thank you for your responses. You have got me thinking now. I am going to double check the cabling to the front case fan and 3 way switch. I might have screwed up there and incorrectly identified the cable.

Noto: LOL

 

[WJA96]

Reaction against txt speak possibly

Then I take it all back. Anyone who is reacting against text speak has my complete sympathy. I can understand why you might use it if you had 9 buttons to press and a sore thumb, but with a full keyboard available, why not use it?

You can't really mis-identify the fan controller - it does have only 3-pin headers on it, although the fans themselves are fitted with both types of connectors. You're probably asking why Lian-Li fitted 4 fans but the fan controller only has 2 headers on it? I am too.

 

[EffBee]

Quick update

Silly me!

I just found a molex connector tucked into a little corner at the top of the case near the front panel 3 speed switch. Only two wires are actually used - yellow and black which I think are 12v and GND so that sorts out the issue of getting power TO the front fan switch and front fan.

The thing I thought was the power to the 3 way switch seems to be a flying lead with a three pin header to attach another fan to the switch and thus takes power FROM the switch.

I'll put a Y cable in this and run the TOP case fan off it. If I decide to put the ducted fan back in the case I'll run that fan off it too.

Does running three case fans off that 3 way switch sound reasonable? Wouldn't want to burn it out. Its not the cost - its the hassle of disassembling half the case to replace it.

So looks like I end up with this:

CPU fan to CPU header on motherboard
Rear Case fan to SYS header on motherboard
NB Motherboard header not used
PWR Motherboard header not used

Front Case FAN (Manufacturer Wired to front panel 3 way switch)
TOP Case Fan (Y Connector) to 3-way switch flying Header
Ducted Case Fan if used (Y Connector) to 3-way switch flying header)

Now to go off and buy lots of extension leads and cable ties for the fan's wires.

 

[cuke2u]

Hi, I tried to control the top and rear fans through the front switch, but all the switch seems to control is the fron fan. Thus I have the top, rear and video card cooler connected to the motherboard, which can allow the control of those fans to be governed by the board, with the front fan connected to a PSU molex via the controller.
The top and front fans blows in, the rear and video card cooler suck out - I left it at that as it seemed to be the best arrangment for my usage...
ChrisC

 

[EffBee]

Thanks Chriscatt - I'll check that out.

Edit: Yes you are right Chriscatt the top case fan has reversed its airflow using the front panel switch's header. I won't be using that then! Thanks again for pointing it out.