CPU Cooler: Fan Speed/Knocking

[v0rtic3s]

I'm running a Zalman 9700 (was running a 9500) on an Intel DBX975XBX2 mobo and C2D, and have it running off the board (3-pin).

However, in this bios there are only two fan speed controls: off and slow, for fan speed moderation.

On slow, the Zalman (both of them) make a slight "knocking" noise - or maybe more accurately, a "pronounced stuttering whirling" - with a slight pitch.

Not too irritating or terrible, but I'm wondering why this is happening?
Is it just the bearings at that speed? Not good, or doesn't matter?

I ordered (lost old ones used to have) the Zalman fanmate speed controllers and wondering if I should use 'em to raise the speed just a little.

Running the Zalmans on full is extremely loud, and not necessary, because on low fan speed my CPU has excellent temps both idle and under load.

Just wondering if it's no good for the fan's bearings and that's why it's doing it, or if it's just because at low this is how the bearings sound.

Thanks.

 

[kill4killin]

You might try using something like speedfan or another program similar to control the speed of the fans plugged into your motherboard's 3 pin connections and see if the same happens.

It is possible if that solves it that it was just the way your motherboard's BIOS regulates the voltage to the fan. If it doesn't solve it and it still makes the noise it's possible that the bearings on the fan are bad. Another clue that the bearings would be bad is try spinning the fan by blowing compressed air on it and then stop the air and see if it makes the noise while free spinning. If it is bearings it probably isn't bad enough to damage anything unless the bearing explodes or something. Otherwise it is just going to be the source of a little extra noise.

 

[cerebrex]

what mobo do you have? If it's a gigbyte - the fan controllers don't respond to speedfan.