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.
(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.
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