Power Supply fan cable to motherboard?

[BoboKatt]

hey all,
I have 2 power supplies. One is a PC&C 750 and one is an older Antec 550 (think it's an TruePower or something). The Antec has a cable that is blue that I can conect to the motherboard where it says Power Supply Fan. The 750 does not.

What is this for? I thought that PS did their own regulation based on load and thus heat to ramp up and down the fan. What is the purpose of benefit of hooking up this fan lead if available. Is it just so the BIOS can monitor to make sure the fan is still running or does it actually slow it down or speed it up?

thanks

 

[bruceb]

You should not need that connection as the fans are internal on most power supplies. I think, it would only be needed if you wanted to feed an auxillary fan from that connector on the motherboard.

 

[Concillian]

Usually that connector is a ground wire and a fan speed wire.

It just allows the motherboard to monitor the PSU fan speed so it can display that and / or trigger an alarm if it stops spinning.

It's not an actual power connector.

 

[bruceb]

I stand corrected on that. I didn't know the mobo would be interested in the power supply fan speed.