Plugging a case fan into the motherboard

[blackwrx]

I just put two more fans in my computer case last night, and I noticed that along with the power cable on the fan, there was also a small 3 pin cable that can plug into the motherboard. There are two places for extra fans to be plugged into my motherboard, and I only have two case fans, so I don't know whether I need to plug them in or not. Right now they're just plugged into the power supply and they're working fine, so what's the purpose of plugging them into the motherboard? Thanks.

 

[mrzeeedler]

YOu can plug them into the motherboard but that would take up your mobos power. And they run at speeds according to how fast your comps running like on load. Like i had one led fan plugged in when comp was just sitting there the leds would flash because they had only got enough power to spin at about 650 rpm. And when it was like 50% cpu usage they had gone up to about 5000rpm and almost spun out. So leave them plugged into the powersupply. WOrks BETteeR!

 

[sithspawn]

I have my case fan plugged into the 'system fan' plug on the motherboard. I have this there so i can monitor the speed of the fan.

 

[mrzeeedler]

Yah sometimes it works and you can monitor it that way. But for me iit just wasnt gonna work because all i had was led fans which blink most of the time becasue its only sending a little power. it will work though you can do it no problem.