Strange Motherboard question

[zod96]

I've got a 120mm scythe fan that when I hook up to the 3 pin header of my Intel X48 motherboard sometimes it spins up other time it does not. What would cause this? I've tried 2 fans already both do the same thing. 50% of the time it spins up fine when booting the computer the other 50% it just sits their. The fans are 800 rpm fans.

 

[DaveSimmons]

Do you have speed control enabled for that fan header in the BIOS? If so, depending on the internal temp the motherboard may be supplying too low of a volatage for the fan.

If the BIOS has different settings for system/case vs. CPU then turn off the system/case fan control so it always runs at full speed.

If there is only one fan control setting get an adapter to run the fan from the PSU instead (a molex / IDE connector)

 

[ZootyGray]

3 pin? 2 pin? u can use a 2 pin on a 3 pin connex if you what pin does what. I used to cheat and use old psu fans this way. Mobo manual should show the electrics for pins on mobo. One pin is a sender/ for the bios reporting. One is ground. One is +12 or +5V.

Various connectors can be adaptors - if u use wrong voltage fan will go really fast Hotwire? Lots of fun.

Various fans are either voltage.

What fan do you have?