Can Smart Fan stop a CPU Fan at low temps or idle?

bgarrant

December 23, 2010 2:06:11 AM

I have a new GIGABYTE x58A-UD3R Rev 2 board running BIOS FD. I noticed when I use AUTO feature of Smart Fan I have noticed that from time to time EasyTune6 and CPUID Hardware Monitor reports a one second stop of the CPU Fan. It is only a second and then it starts back up. I do not actually hear it stop, but it reports in software RPMs of 0. The BIOS CPU Fan alarms is also enabled but does not make any alarm sound. I am using a Cooler Master V8 Cooler and an i7 950 CPU.

Can the softwar be reporting a bad reading at low temo or IDLE times? Could the heat pipes be cooling when temp is low and actual fan stopping?

When I disable Smart Fan in EasyTune6, the V8 runs at full 2000 RPMs and has no issues so it seems the controller is fine. Do I need to worry? My temps stay below 30C most of time. Is it a software glitch or a MOBO issue? DOes Intel have a process that could stop fan as I am using PWM for Smart Fan control?

Thanks in advance.

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alyoshka

CPUs Authority

December 23, 2010 9:47:18 AM

No, it does not stop the fan. Actually there is a minimum RPM limit for that, the warning should come only when it crosses you minimum RPM limit.
If you have 2 different values set in the BIOS and the Software then, when the Value drops below the Software RPM value you'll have a Software Alarm and if it drops below the BIOS RPM limit then you'll have the BIOS Alarm going off.
Basically both the minimum values should be set to the same.
As long as the Fan doesn't come to a complete stop, you really don't have much to worry about, also, if the temps don't climb to high, again you've got nothing to worry about.
Yes sometimes you do find faulty readings with software's.....

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apache_lives

CPUs Expert

December 23, 2010 11:33:07 AM

gigabyte has this issue - AUTO for some reason defaults to voltage control for the fan - manually set it to PWM to fix it

what happens is the cpu temp is low so the AUTO setting (aka voltage control for fan speed etc) lowers the voltage to the cpu fan too low so it spins, then stops etc until it gets hot so it raises the power to the fan enough to spin.

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bgarrant

December 23, 2010 12:40:42 PM

apache_lives said:

gigabyte has this issue - AUTO for some reason defaults to voltage control for the fan - manually set it to PWM to fix it

what happens is the cpu temp is low so the AUTO setting (aka voltage control for fan speed etc) lowers the voltage to the cpu fan too low so it spins, then stops etc until it gets hot so it raises the power to the fan enough to spin.

Since the BIOS CPU Fan Warning never goes off I have to believe there is no issue as well. It only happens for a second or so and then it is right back up to speed. No sound change is heard. To test, I set it at full 2000 RPMs with SmartFan disabled. I then looked at monitor and saw that it stated a drop for a second down to 198 RPMs. I can hear the fan very well and no change was heard when this was reported. Do you also believe it is just a software issue as the BIOS Fan alarm does not sound? I did set to PWM and same issue was reported.

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