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CPU - Fan Constant Throttling

Last response: in Components
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June 20, 2010 4:23:31 PM

Hi folks,

I recently mounted a TMG IA1 CPU cooler on my Propus at stock speeds (stock cooler kept breaking the 70c barrier when performing video encoding). Now with the TMG IA1, it won't go past 49c, so that's awesome.

Anyhow, one thing I've noticed about the fan is that when it's idling, it stays at about 800 rpm. However, once the temperature gets into the 40 ~ 49c zone, the fan keeps throttling up to about 1800~1900 rpm for about 5 seconds, before either throttling down, or the mobo cuts off power to the fan or something. It's a 3-pin header, so it's using volts to throttle the speed.

My question is....is this normal?

I have Cool and Quiet enabled, and I have CPU-Fan control enabled. I have set it in the mobo to use volts specifically to control the fan speeds.

When I had the stock cooler, I would not hear such rampant fan throttling. Instead, it would be gradual, nothing like what I'm hearing now. Is my mobo unable to provide continuous power to keep the fan going at that RPM? Or is it really the sensors forcing the fan to keep going back down to default speeds once the temperature has dropped below a certain level?

And finally, is this constant throttling going to mess up the life of the fan?

Thanks everyone if you're able to help me answer my questions and solve this weird throttling problem.

P.S. The mobo I'm using is the GA-MA790GPT-UD3H.

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a b à CPUs
June 20, 2010 6:34:27 PM
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Your fan is just doing what it's told by the various hardware and software systems you have in place so yes it's normal. Doing it through volts as opposed to PWM may well be cause these sudden bursts instead of a smooth transition, but it's still doing what it's supposed to be doing.

I shouldn't think the fan would be affected by this, but I always do PWM for my CPU fan so I couldn't say for sure.
June 20, 2010 9:32:34 PM

i would just mess around with the fan controls in the bios a little. some tinkering should fix the problem.
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June 20, 2010 9:39:27 PM

I concur, and meant to say something similar. You could try putting the thermal threshold of the fan up or down a few degrees to trigger the spin-up later or sooner for more consistent fan operation.

As long as the fan isn't too loud it won't hurt to drop the threshold a bit and have the fan going consistently faster for longer.
June 20, 2010 11:56:20 PM

Thanks everyone for your reply, it's comforting to know that I didn't get a defective unit.

Where exactly in the bios can I adjust fan-speeds? That'd be interesting to know. Also, if it matters, the TMG IA1 comes with a variable fan control knob. It's currently set to the lowest (I turned it all the way down before mounting the fan).

And Phuronn, I kinda figured it's something to do with the fan being controlled by volts as opposed to PWM.

Cheers guys, this makes me feel much better.
June 20, 2010 11:56:32 PM

Best answer selected by poisonwolf.
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