Hi I have had total headache trying to get someone to tell me what I need to plug 2 fans into one mobo header (days now) in the end I couldn't get anyone to answer me,so I'm hoping I can here or I think I'll just give up!! I have had to chance cases because my old one was to big for my new desk however it had fan control built into to the case so I've never had to deal with fans and tbh it's becoming harder to understand than building the dam thing!! anyway I bought a smaller case and it has one 80mm rear fan and 120mm front fan. So after countless Internet reading I've bought these one 80mm and one 120mm https://www.amazon.co.uk/ARCTIC-F12-PWM-Rev-2-Controlled/dp/B00H3T1KBE/ref=pd_rhf_gw_p_img_1?_encoding=UTF8&psc=1&refRID=N2ZV5GH7X4P23YGB344M and this https://www.amazon.co.uk/Akasa-AK-CBFA04-15-Splitter-Cable-Fans/dp/B005FWXWPS/ref=pd_bxgy_147_img_2?_encoding=UTF8&psc=1&refRID=TKNVFNEGF5NNNYREGHEM
Anyway I have a b250m d2v mobo and now that I've read a little more it seems it wouldn't be a good idea to plug to different fans into that splitter and both have different max rpm. Can anyone point me in the right place to what I need? I read that you can buy a 4 pin to 4-3 pin splitter and than it only reads one fan? also which one would I plug into the 4 pin the one with max rpm? Would really appreciate being lead by the hand here and links if possible as at this stage I feel like just buying some molex ones and having done with.
Edit"" OK after looking at the splitter I have bought (not yet dispatched) it does seem the pin is missing on one for rpm feedback. If this is the case and all is OK can someone tell with one of the fans I should plug into the 4 pin? And is it OK to have different sizes, rpm ect. Cheers
The 80mm one has 2000rpm and the 120mm has 1350rpm which one should I plug into the 4 pin header? Will it make a difference as one has more than the other, and is there anything else that's different that might affect them? Thanks
The 80mm one has 2000rpm and the 120mm has 1350rpm which one should I plug into the 4 pin header? Will it make a difference as one has more than the other, and is there anything else that's different that might affect them? Thanks
Would it not matter with one being faster? Say the 2000rpm one making the 1350rpm spin faster and damage it? Sorry I'm totally clueless I thought that was what the pwm was for to control how fast they spin making one spin faster than 1350rpm if I plug the 2000rpm one in
Would it not matter with one being faster? Say the 2000rpm one making the 1350rpm spin faster and damage it? Sorry I'm totally clueless I thought that was what the pwm was for to control how fast they spin making one spin faster than 1350rpm if I plug the 2000rpm one in
Motherboard sends 7-12 volt for 3-pin fan and PWM signal to PWM fans (4-pin fans), but motherboard does not pay attention to rpm of fan. Voltage or PWM signal is determined by temperature of component. The RPM signal is for use to know fan's speed .. and sometimes for motherboard to know fan has stopped turning.
Motherboard monitors component temperature and increases / decreases fan power /speed to get more or less airflow through cooler. Most if not all motherboard do not use the actual fans speed in rpm, .. same as they don't monitor the airflow. If there is too much airflow and component cools down too much the motherboard lowers the power to fan / lowers the airflow. If component is too hot motherboard increase power to fan / increases airflow.
You can try it both ways, but I'm betting it makes no difference.
Motherboard sends 7-12 volt for 3-pin fan and PWM signal to PWM fans (4-pin fans), but motherboard does not pay attention to rpm of fan. Voltage or PWM signal is determined by temperature of component. The RPM signal is for use to know fan's speed .. and sometimes for motherboard to know fan has stopped turning.
You can try it both ways, but I'm betting it makes no difference.
OK I sort of understand that, so it shouldn't make a difference how much power it puts out on the one header pwm or whatever it means as, the fans will only take the maximum it can and spin at whatever speed it can achieve? Sorry I just thought that whatever the rpm it reported ment what it would do. And didn't know if this would affect it if the fans were different
OK I sort of understand that, so it shouldn't make a difference how much power it puts out on the one header pwm or whatever it means as, the fans will only take the maximum it can and spin at whatever speed it can achieve? Sorry I just thought that whatever the rpm it reported ment what it would do. And didn't know if this would affect it if the fans were different
no they are 4 pin fans I posted a link in first post but haven't received them yet. That's why I'm confused on this pwm malaky, and don't know if it will work like it should with them being different sizes speeds ect.. I understand that the pwm controls the speed of how fast they should spin but I assume it can only read one fan not both. so this is what it confusing me. As I read on other threads that I may need one 3 pin and one 4 pin. But then I'm so bamboozled now
If the 4-pin fan header you use is really a PWM fan header it will control both fans with PWM signal. If your 4-pin fan header is not PWM it will control both fans with variable voltage.
PWM has rpm on pin-3 same as 3-pin fans. Pin-1 is ground and pin-2 is power, but PWM is 12 constant power on pin-2 and variable voltage is variable voltage on pin-2. Pin-4 is PWM signal for PWM fans. But PWM fans work on variable voltage too.
Generally the only fan header on motherboard that is PWM is CPU fan header. Some new motherboards have more PWM headers, but do not thing just because the motherboard has 4-pin fan header they are PWM because the are often only using 3-pins and are variable voltage fan headers.
I know, it sound confusing, but it's not as bad as it sounds.
If the 4-pin fan header you use is really a PWM fan header it will control both fans with PWM signal. If your 4-pin fan header is not PWM it will control both fans with variable voltage.
PWM has rpm on pin-3 same as 3-pin fans. Pin-1 is ground and pin-2 is power, but PWM is 12 constant power on pin-2 and variable voltage is variable voltage on pin-2. Pin-4 is PWM signal for PWM fans. But PWM fans work on variable voltage too.
Generally the only fan header on motherboard that is PWM is CPU fan header. Some new motherboards have more PWM headers, but do not thing just because the motherboard has 4-pin fan header they are PWM because the are often only using 3-pins and are variable voltage fan headers.
I know, it sound confusing, but it's not as bad as it sounds.
I read a little more and it seems if it's right it doesn't matter if one fan runs at 1030rpm and one runs at 2000rpm on a splitter it should let's say if the Temp sensors says it needs 50% power fan A Should run at 515rpm and fan B at 1000rpm and so on. I have a b250m d2v mobo so it has built in sensor voltage protection anyways and other bells and whistles. If it was that important I'm sure it wouldn't have taking me 2 days already to find answers. Thanks for your time. Feel free to add anyone if I'm still incorrect and I'm going to blow it up ?
Just use the splitter and plug both fans in. They will spin at their relative speed (as you said in your post above) based on the PWM signal they are receiving (i.e., as a percentage of their maximum speed).
I read a little more and it seems if it's right it doesn't matter if one fan runs at 1030rpm and one runs at 2000rpm on a splitter it should let's say if the Temp sensors says it needs 50% power fan A Should run at 515rpm and fan B at 1000rpm and so on. I have a b250m d2v mobo so it has built in sensor voltage protection anyways and other bells and whistles. If it was that important I'm sure it wouldn't have taking me 2 days already to find answers. Thanks for your time. Feel free to add anyone if I'm still incorrect and I'm going to blow it up ?
Basically correct in general turns, but very few fans have linear PWM% to RPM ratios. Alm,ost all PWM fans have their own PWM% to RPM curve and few are the same. Here is a collection of Thermalbench PWM% to RPM curves.
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