4 pin cpu fan connector but only 3 pin on motherboard

[tmslaw]

I just installed an Opteron 185 with the included fan/heatsink on an Asus A8N-SLI Deluxe motherboard. The fan has a 4 pin connector but the motherboard only has a 3 pin connector for a cpu fan. The cpu and motherboard are supposed to be compatable. Can anything be done short of buying a 3 pin fan?

 

[MikeyJ79]

If by 4-pin you mean that it looks like a connector that would plug into a hard drive or CD/DVD drive, except that it has a male connection, you can use those same "drive" plugs to connect your fan. Just plug one of the 4-pin connectors from your power supply (also known as a molex connector) into the male connector for your fan.

It does seem odd that the included fan uses the 4-pin connector. Was this a retail boxed processor, and has anyone had this experience with retail boxed processors recently? All I've known to be bundled with processors these days are fans with 3-pin plugs.

Unfortunately, to the best of my knowledge, using a 4-pin connector loses you sensor capabilities, meaning you won't be able to detect the RPMs through any common means (i.e. BIOS, software), not that I am aware of any other means personally.

I hope this helps.

 

[sjandrewbsme]

That's a universal fan meant to be used on any number of boards (and for applications other than on a CPU). You can plug it directly into you power supply.

What sucks about doing it this way is you will get no RPM monitoring from your motherboard. This may not matter, but these fans tend to be very fast and very loud. Since you won't have the ability to slow them down in the BIOS (since they con't be connected to the motheboard) you might want to get some earplugs.

 

[colin324]

It has 4 pins for pwm control by the motherboard. It should fit onto a 3 pin header (ridges on connector ensure correct polarity). The fourth pin allows the motherboard to control the speed of the fan. Where this is not fitted, I believe it defaults to maximum speed.

Colin.

 

[Pelltuk]

I know that this is an old subject. I have just resurrected an old PC which has got a NEC Bogota MS-7295 MB and is fitted with an AMD 2 processor. Because the fans were making so much noise I decided to replace them all with super quiet ones. The CPU & heatsink combo is a Gelid Siberian Pro and is perfectly adequate for what I require, but comes with a 4 pin connector and my MB has a 3 pin header. No problem I hear you say just leave plug over hanging, the fan will just run at full speed.
When I switched on the PC, the fan ran for about 10 seconds then stopped and the blades were just twitching slightly, after about 10 minutes of no fan activity I decided to check temp of heatsink. It was getting rather hot to the touch so I switched off.
I have got another old cpu fan with a 4 pin connector so tried that with same results, looking at connector wiring it was Black,Red, Blue then Yellow ( cant tell on new fan as all are black) Now I have always been told that the blue is the pulse line for speed control not Yellow, switching these 2 around in the connector now lets fan run at full speed so did the same swap on the black wires.
Any thoughts or comments would be gratefully received as I would rather the fan did not run at full speed all the time.