Please report all spam threads, posts and suspicious members. We receive spam notifications and will take immediate action!
Page 1 of 3 123 LastLast
Results 1 to 10 of 22

Thread: EP35C-DS3R Fan headers and sensors




  1. #1
    Join Date
    Sep 2008
    Posts
    10

    Default EP35C-DS3R Fan headers and sensors

    Here's my first big question. I actually asked this question on another forum sometime back. I'm just going to cut and past it here.

    Here's how they are explained in the manual.

    CPU_FAN
    Pin 1:GND
    Pin 2: +12v
    Pin 3: Sense
    Pin 4: Speed control

    SYS_FAN 1
    Pin 1: GND
    Pin 2: +12v
    Pin 3: Sense

    SYS_FAN 2
    Pin 1:GND
    Pin 2: Speed Control
    Pin 3: Sense
    Pin 4: +5v

    PWR_FAN
    Pin 1: GND
    Pin 2: +12v
    Pin 3: Sense

    Ok, the CPU fan and SYS_FAN 1 are understandable.

    As for SYS_FAN 2, why does it output only 5 volts? Is this header intended to have a specific purpose and run a specific 5 volt fan? Also, why is the voltage output on a different pin than the CPU header? Speed control and output have been swapped.

    While the PWR_FAN header is pinned out the same as SYS_FAN 1, the name throws me. It makes me think that it is attached to a specific temp sensor on the board...ah, which brings me to another question.

    Looking at Gigabyte's windows utility, it shows a CPU temp and a SYS temp. However, if I look at "Speed Fan", it shows the same plus two more sys temps with very low readings (like around freezing). I would assume that the low readings indicate that there isn't a sensor?

    So, if there is one sensor for sys temp, where is it located? I ask because it generally shows a higher temp than the CPU. I assume it would be controlling SYS_FAN 2 since it is a 4-pin header. However, the 5 volts still is a mystery.

    Sorry for the rather long post there. I know it's alot of questions and I apologize for that. Anyone wanna try and tackle them? :D

  2. #2
    Join Date
    Apr 2008
    Posts
    942

    Default Re: EP35C-DS3R Fan headers and sensors

    Quote Originally Posted by Danaf View Post
    Here's my first big question. I actually asked this question on another forum sometime back. I'm just going to cut and past it here.

    Here's how they are explained in the manual.

    CPU_FAN
    Pin 1:GND
    Pin 2: +12v
    Pin 3: Sense
    Pin 4: Speed control

    SYS_FAN 1
    Pin 1: GND
    Pin 2: +12v
    Pin 3: Sense

    SYS_FAN 2
    Pin 1:GND
    Pin 2: Speed Control
    Pin 3: Sense
    Pin 4: +5v

    PWR_FAN
    Pin 1: GND
    Pin 2: +12v
    Pin 3: Sense

    Ok, the CPU fan and SYS_FAN 1 are understandable.

    As for SYS_FAN 2, why does it output only 5 volts? Is this header intended to have a specific purpose and run a specific 5 volt fan? Also, why is the voltage output on a different pin than the CPU header? Speed control and output have been swapped.

    While the PWR_FAN header is pinned out the same as SYS_FAN 1, the name throws me. It makes me think that it is attached to a specific temp sensor on the board...ah, which brings me to another question.

    Looking at Gigabyte's windows utility, it shows a CPU temp and a SYS temp. However, if I look at "Speed Fan", it shows the same plus two more sys temps with very low readings (like around freezing). I would assume that the low readings indicate that there isn't a sensor?

    So, if there is one sensor for sys temp, where is it located? I ask because it generally shows a higher temp than the CPU. I assume it would be controlling SYS_FAN 2 since it is a 4-pin header. However, the 5 volts still is a mystery.

    Sorry for the rather long post there. I know it's alot of questions and I apologize for that. Anyone wanna try and tackle them? :D
    I can only assume that is a misprint or misintepretation, because the 4 pin type headers have to follow a standard, ie that for external controlled PWM fans.

    As you are probably aware you can connect a 3 pin fan to the header, but it will run at maximum. (unless the board has linear voltage control on pin 2)
    All the 4th pin does is control the PWM (or mark space ratio) of the fan control, allowing it to be driven at a wide range of speeds (greater voltage range vs linear voltage control) from an external "digital" source, such as the bios etc.

    As for the "5v" issue, you may well find it even measures around 5vdc but this may also imply (or be an indicater) that the PWM signal follows a standard (that GB are adhering to) and that pin will not exceed 5 volts. (even though it is essentially just a signal/control line)
    http://www.formfactors.org/developer...e_PWM_Spec.pdf
    Edit:
    After reading the data sheet (above) a constant 5 volts (ie constant "marks" no "spaces" etc 100% duty cycle = Full Speed fan.
    So what GB are probably saying, is that if FAN 2 has no variable control in the bios and you connect a 4 pin pwm fan - it will run flat out!
    They could have worded it better (and so could have I), but basically 5volts on pin 4 equates signal wise for the fan to go Flat OUT.

    They are probably also saying, 'although we gave you a second 4 pin fan header on your board, unlike the CPU fan header, the fan 2 header has no variable control via the motherboard - as such a 4 pin fan will run at max speed if connected to it.


    For reference too; my P35 manual states exactly the same pin out for the TWO 4 pin sockets:-

    1) CPU_FAN
    2) SYS_FAN 2

    Pins:-
    1 = Ground
    2 = +12v/Speed Control***
    3 = Sense (ie tacho)
    4 = Speed Control (ie (PWM)

    *** Can only assume they stated "Speed Control" for pin 2 aswell as 12vdc, as if the header is used with a standard 3 pin fan, that if the DC voltage were to be varied on that pin, then that would change the fans speed.

    PS:
    Try HWMonitor or PCwizard from CPUID
    I prefer them to speedfan, as in general I have found them more accurate.
    Last edited by VorLonUK; 09-26-2008 at 09:02 AM.
    GA-P35C-DS3R Rev2.0 F11 bios, E8200 (@3.0Ghz), OCZ DDR3 PC3-10666 Reaper 4GB (@1200Mhz), Xonar D1, 8800GTS 512, Corsair HX520 (Single 12volt line, Max 40A), WDC 3200aaks/5000aaks in AHCI mode, Vista 64 Premium.

  3. #3
    Lsdmeasap's Avatar
    Lsdmeasap is offline GIGABYTE Guru
    Join Date
    Jan 2008
    Location
    PCB Island
    Posts
    25,940

    Default Re: EP35C-DS3R Fan headers and sensors

    Quote Originally Posted by Danaf View Post
    Here's my first big question. I actually asked this question on another forum sometime back. I'm just going to cut and past it here.

    Here's how they are explained in the manual.

    CPU_FAN
    Pin 1:GND
    Pin 2: +12v
    Pin 3: Sense
    Pin 4: Speed control

    SYS_FAN 1
    Pin 1: GND
    Pin 2: +12v
    Pin 3: Sense

    SYS_FAN 2
    Pin 1:GND
    Pin 2: Speed Control
    Pin 3: Sense
    Pin 4: +5v

    PWR_FAN
    Pin 1: GND
    Pin 2: +12v
    Pin 3: Sense

    Ok, the CPU fan and SYS_FAN 1 are understandable.

    As for SYS_FAN 2, why does it output only 5 volts? Is this header intended to have a specific purpose and run a specific 5 volt fan? Also, why is the voltage output on a different pin than the CPU header? Speed control and output have been swapped.

    While the PWR_FAN header is pinned out the same as SYS_FAN 1, the name throws me. It makes me think that it is attached to a specific temp sensor on the board...ah, which brings me to another question.

    Looking at Gigabyte's windows utility, it shows a CPU temp and a SYS temp. However, if I look at "Speed Fan", it shows the same plus two more sys temps with very low readings (like around freezing). I would assume that the low readings indicate that there isn't a sensor?

    So, if there is one sensor for sys temp, where is it located? I ask because it generally shows a higher temp than the CPU. I assume it would be controlling SYS_FAN 2 since it is a 4-pin header. However, the 5 volts still is a mystery.

    Sorry for the rather long post there. I know it's alot of questions and I apologize for that. Anyone wanna try and tackle them? :D
    Here is what our fellow member SvcGglobal has found with some testing

    CPU_FAN connector needs a CPU cooler with four wires were the PWM modulator is included in the cooler. The mobo senses the CPU temperature and managing the pin 4 signal, the cooler's fan will automatically be increased or decreased, following the CPU temp. Fan's rotation feedback returns via pin 3 for BIOS alarm feature.

    SYS_FAN2 connector needs any fan, with three or four wires (don't care) since the speed is controlled via on-board PWM controller that supply pulse-width-modulated 12v for the fan via pin 2.
    So, if using a four wire fan, its internal PWM is locked to full speed (this explain that fixed 5v on pin 4).
    This time, the mobo senses the North Bridge (in my case the P35) temperature and will increase or decrease the speed of the fan connected in this socket. Feedback is sent to pin 3 for BIOS alarm purposes.

    SYS_FAN1 and PWR_FAN are three pin socket with fixed full speed fan. No controlled rotation at all from the mobo. Rotation feedback also monitored via pin 3 only for BIOS alarm purpose.
    As for the "System" temp, that is your Northbridge, also called Motherboard in other apps. The two Lower or incorrect looking settings in speedfan could be any number of things like a incorrectly picked up sensor or one that needs to be configured manually? Can you install everest and compare them?

  4. #4
    Join Date
    Apr 2008
    Posts
    942

    Default Re: EP35C-DS3R Fan headers and sensors

    From my post above, the factual/technical info:-

    http://www.formfactors.org/developer...e_PWM_Spec.pdf
    GA-P35C-DS3R Rev2.0 F11 bios, E8200 (@3.0Ghz), OCZ DDR3 PC3-10666 Reaper 4GB (@1200Mhz), Xonar D1, 8800GTS 512, Corsair HX520 (Single 12volt line, Max 40A), WDC 3200aaks/5000aaks in AHCI mode, Vista 64 Premium.

  5. #5
    Join Date
    Sep 2008
    Posts
    20

    Default Re: EP35C-DS3R Fan headers and sensors

    Gigabyte claims that sysfan2 does indeed output 12V, and that the 5V is a typo. I think the real answer lies somewhere in between. Most people have reported that connecting a 3-pin (non-PWM) fan to sys_fan2 will in fact run at 5V. So it's not a typo. But, if you connect a 4-pin PWM fan to it, you can get it to run at 12V.

  6. #6
    Join Date
    Apr 2008
    Posts
    942

    Default Re: EP35C-DS3R Fan headers and sensors

    Quote Originally Posted by auroa View Post
    Gigabyte claims that sysfan2 does indeed output 12V, and that the 5V is a typo. I think the real answer lies somewhere in between. Most people have reported that connecting a 3-pin (non-PWM) fan to sys_fan2 will in fact run at 5V. So it's not a typo. But, if you connect a 4-pin PWM fan to it, you can get it to run at 12V.
    What should happen is:-

    Pin1 = ground
    Pin2 = 12 vdc
    Pin3 = tacho
    Pin4 = PWM (mark, space ratio switching)

    If you connect a 3 pin fan, all it relies on is the 12volts and ground connections to work. The tacho pin is optional.

    If you connect a 4 pin fan, it relies on the 12 volt supply, Ground and a PWM signal before it can do anything. The tacho pin is again optional.

    The idea of a control wire (ie the pwm one) is so that you do not need to use a linear voltage control (that creates heat) to vary the supply voltage to inturn change the fans speed.

    By using a PWM fan, the 12 volt supply is a CONSTANT and the PWM (varying of the mark space ratio) pin is what effectively controls the speed. The beauty of this is you don't have to have a linear dc voltage control and it is more green as the fan is switched on and off at 25khz for varying lengths of time (mark space ratio) to give you your final speed.

    The draw backs are as the fan is being switched on and off rapidly (25khz) this can lead to some unwanted noise from the fan. Whereas varying the DC voltage to a 3 pin fan, with a linear voltage controller creates no noise as it's a constant and not switching.

    Edit (after checking with my DVM):- I can confirm too, that SYS_FAN 2 on my P35 board does NOT follow the 4 pin pwm fan standard (as the CPU header does). Instead they have made it into a Hybrid connection and indeed the voltage on Pin 2 which should be a steady 12volts (as per the 4pin fan standard) does appear to vary on system temperature (=>8 volts). I haven't determined if that is based on Northbridge, MB temperature etc.
    I can see why Gigabyte may have done this though. It can allow both a 3 pin or 4 pin fan to be temperature controlled via the board, although you have no control of this.
    Pin 4 though should be 0 volts when a fan isn't connected, as it is a 4 pin fans job to "pull up" the voltage to no more than 5.25volts for the PWM signal. I can only assume Gigabyte have set Pin 4 of the header to 5 volts on the rogue SYS_FAN 2 to ensure that if a 4 pin fan is connected it will run at 100% duty cycle and thus the supply voltage of Pin 2, as a 3 pin fan would.
    Last edited by VorLonUK; 09-27-2008 at 08:36 AM. Reason: New Info
    GA-P35C-DS3R Rev2.0 F11 bios, E8200 (@3.0Ghz), OCZ DDR3 PC3-10666 Reaper 4GB (@1200Mhz), Xonar D1, 8800GTS 512, Corsair HX520 (Single 12volt line, Max 40A), WDC 3200aaks/5000aaks in AHCI mode, Vista 64 Premium.

  7. #7
    Join Date
    Sep 2008
    Posts
    10

    Default Re: EP35C-DS3R Fan headers and sensors

    Ok, my head is spinning!

    What amazes me with all this is the fact that we don't know. Why won't Gigabyte simply provide that info?

    Ok, so the hottest temp I see on my board (excluding the cpu of course) is apparently the Northbridge temp. I would like to have the board CONTROL and VARY the speed of a fan to cool the Northbridge. Therefore, if I'm understanding all of you correctly, the Northbridge temp sensor CONTROLS sys_fan2. Is this correct?

    If it is, do I use a 3 pin or 4 pin fan?

  8. #8
    Join Date
    Sep 2008
    Posts
    20

    Default Re: EP35C-DS3R Fan headers and sensors

    Now that I look at it, I think Gigabyte just doesn't want to have people running a 2nd or 3rd case fan at a full 12V, making the computer louder than it needs to be. After all, the NB heatsink is probably by itself sufficient cooling at stock voltages. I would think a small fan at 5v blowing at it would be more than enough for all but the most extreme OC'ers.

  9. #9
    Join Date
    Apr 2008
    Posts
    942

    Default Re: EP35C-DS3R Fan headers and sensors

    Quote Originally Posted by auroa View Post
    Now that I look at it, I think Gigabyte just doesn't want to have people running a 2nd or 3rd case fan at a full 12V, making the computer louder than it needs to be. After all, the NB heatsink is probably by itself sufficient cooling at stock voltages. I would think a small fan at 5v blowing at it would be more than enough for all but the most extreme OC'ers.
    Well when you look at the way Gigabyte have designed the board, the stock Intel fan which i use on my P35 (as it's incredibly quiet) blows down through the Heatsink towards the board. As it does that, the air on the Northbridge side runs over the extra wide Northbridge Heatsink. A clever design imo.

    Obviously the air isn't as cool or likely accelerated as a seperate Northbridge fan could provide, but it does go partly towards ensuring the NorthBridge isn't just passively cooled.
    GA-P35C-DS3R Rev2.0 F11 bios, E8200 (@3.0Ghz), OCZ DDR3 PC3-10666 Reaper 4GB (@1200Mhz), Xonar D1, 8800GTS 512, Corsair HX520 (Single 12volt line, Max 40A), WDC 3200aaks/5000aaks in AHCI mode, Vista 64 Premium.

  10. #10
    Join Date
    Oct 2010
    Location
    Greece
    Posts
    109

    Default Re: EP35C-DS3R Fan headers and sensors

    QUOTE=VorLonUK : Well when you look at the way Gigabyte have designed the board, the stock Intel fan which i use on my P35 (as it's incredibly quiet) blows down through the Heatsink towards the board..................... but it does go partly towards ensuring the NorthBridge isn't just passively cooled./QUOTE

    Lets bump up this thread

    The idea of " sharing " cooling with other near by components it happens and it works.

    But you can not limit your choice of selecting other coolers, just because of that.

    Currently at 2010-2011 there is an technical solution , called as Nanoxia PWM-X ,
    that it does convert the PWM signals in to DC.

    And so by getting this tiny " translator " you can power up any 3 Pin fan, that eventually he will variate his speed according to PWM signals.

    I did in-depth tests, and found that the PWM motherboard header ( CPU Fan ),
    are able to variate the PWM output at just 5 levels .

    Five levels PWM equals to five possible rotation speeds,
    like the fixed gear box of a car.

    Those Five levels PWM output , was set by having in mind , that the output will be used from the stock INTEL fan.

    And so the " Gear 5 " represents the maximum rotation speed of the INTEL fan,
    that is about 1600 - 1700 RPM or so.

    At the PWM fan headers , the 12V or 5V header pin ( stable DC ) will supply voltage just for the operation of the circuitry of the fan (electronic parts on the PCB).
    This voltage its not necessary to be 12V , the PWM fans needs from 5v up to 12V. ( just for the PCB - circuity ).

    The PWM fan, will get all the power that he needs to spin (motor voltage), from the PWM signal .
    And so only the PWM pin will be stressed if you use an large fan on it, that exceeds the Fan header PWM specs.

    And now that everything is explained , I need to know what are the true Fan Header specs, for its one header and Pin ?

    Personally I have an picture by just guessing from the INTEL fan specs.

    PWM header :
    PWM Pin = 350mA ( Intel fan needs 200mA Max )
    + 5 up to 12 Pin = 450mA ( classic 3 Pin fans are more power hungry)
    Pin Ground .. ( Its the PCB it self )
    RPM detection .. ( just what it says ) ( Does not supply power )

    If some one are skilled in electronics ( heavily skilled )
    I invite him to join and read alternative ways of making your own PWM to DC converter.
    ( You have to register, so to see the pictures , and its free)

    I all ready got the Nanoxia PWMX , but I am also making and my own circuit,
    with the help of those electronic engineers in the forum.

    http:
    //www.eevblog.com/forum/index.php?topic=1604.0


    And some pictures of what I am talking , in here ..
    GA-EP35C-DS3R & (2x2gb) pc12800 DDR3 1600Mhz

    Happy reading




    .
    Last edited by Kiriakos; 12-02-2010 at 04:02 AM.
    EP35C-DS3R F4 | Q6600 | ProlimaTech Armageddon
    HYPER-X KHX1600C8D3T1K2 /4GX
    PC3-12800 1600MHz (1066 CL 6-6-6-21)
    ATI HD 5770 Vapor - X| X-Fi music |RAID-1 WD Raptors
    HIPER HPU-4M780-PE

    XP PRO 32bit

Page 1 of 3 123 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •