+bomberh Subscriber² Posted February 18, 2010 Subscriber² Share Posted February 18, 2010 I am building a new computer and I will be using the Corsiar H50 CPU water cooler. The cooler comes with a fan which you screw to the H50 radiator and this fan has a 4 pin connection. In the instructions it shows the fan being connected to the 4 pin CPU header on the MB. The fan that comes with this kit isn?t the best so I have decided to change the fan. The only thing is the fan I have only has a 3 pin connection. If I do not attach anything to the 4 pin CPU header on the MB, will there be a problem? Will it stop the computer from starting because it doesn?t think the CPU has a working fan. Or can I just plug the 3 pin fan into the CPU header and all will be fine? Thanks for any help. Link to comment https://www.neowin.net/forum/topic/876472-4-pin-motherboard-cpu-fan-header/ Share on other sites More sharing options...
TokiToki Posted February 18, 2010 Share Posted February 18, 2010 Plugging the 3-pin is fine. The only issue is if the motherboard cannot control the fan voltage on the 3-pin, the fan will run at full speed. My Asus motherboard requires a 4-pin fan for automatic fan control, whereas my Gigabyte motherboard is able to automatically control a 3-pin as well. Link to comment https://www.neowin.net/forum/topic/876472-4-pin-motherboard-cpu-fan-header/#findComment-592254968 Share on other sites More sharing options...
+bomberh Subscriber² Posted February 18, 2010 Author Subscriber² Share Posted February 18, 2010 Plugging the 3-pin is fine. The only issue is if the motherboard cannot control the fan voltage on the 3-pin, the fan will run at full speed. My Asus motherboard requires a 4-pin fan for automatic fan control, whereas my Gigabyte motherboard is able to automatically control a 3-pin as well. I need it to run at 100% as it will be keeping my H50 CPU water cooler radiator cool which in turn will keep my CPU cool. If I don't plug anything in the 4 pin CPU fan header, will that be ok too?? Cheers Link to comment https://www.neowin.net/forum/topic/876472-4-pin-motherboard-cpu-fan-header/#findComment-592255006 Share on other sites More sharing options...
Rob2687 Posted February 18, 2010 Share Posted February 18, 2010 It will be okay without the 4th pin. The connector designed to support 3-pin or 4-pin fans. The 4th pin is the fan speed control. Link to comment https://www.neowin.net/forum/topic/876472-4-pin-motherboard-cpu-fan-header/#findComment-592255018 Share on other sites More sharing options...
Lewism Posted February 18, 2010 Share Posted February 18, 2010 I need it to run at 100% as it will be keeping my H50 CPU water cooler radiator cool which in turn will keep my CPU cool. If I don't plug anything in the 4 pin CPU fan header, will that be ok too?? Cheers I did a mistake like this when I built a PC yesterday. I plugged the CPU fan in the chassis fan 3 pin instead the CPU fan 4 pin. The board was a Asus. It booted but it gave me a warning at boot. Each time I booted, I had to hit F1 to bypass the warning. Link to comment https://www.neowin.net/forum/topic/876472-4-pin-motherboard-cpu-fan-header/#findComment-592255026 Share on other sites More sharing options...
robyholmes Posted February 18, 2010 Share Posted February 18, 2010 Its fine to use a 3pin fan connector on a 4pin one. The 4th pin is used for controlling fan speed on some newer coolers were as the old style 3pin would just reduce the voltage to the fan. The 4th wire is used so the fan gets full voltage all the time but the mobo can supply it with less (I think on the 4th pin). See what I am getting at? (I think I am right) Your radiator fan shouldn't need to run at 100% all the time tho. When you have got it all put together jump in to BIOS and in 'Hardware Monitor' or 'Power' there should be a 'CPU Smart Fan' were you can set a profile 'Performance/Silent' or target temp. This should be able to control the fan speed based on the temperature readout from the CPU socket. You might want to check its reading right in BIOS to, should be in the same place as fan controls. Make sure its like 20-40c, then you know its correct and the fan will change speed depending on your target temp and the current temp. Good Luck I did a mistake like this when I built a PC yesterday. I plugged the CPU fan in the chassis fan 3 pin instead the CPU fan 4 pin. The board was a Asus. It booted but it gave me a warning at boot. Each time I booted, I had to hit F1 to bypass the warning. This can be disable in BIOS too, sometime when using a fan controller you don't require the CPU fan header. Link to comment https://www.neowin.net/forum/topic/876472-4-pin-motherboard-cpu-fan-header/#findComment-592255038 Share on other sites More sharing options...
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