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**sygnus21** · 12-22-2010, 10:18 PM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

Hmmm.... haven't seen that, or noticed an issue with my monitoring program like AIDA64 (Everest). On the other hand I don't use Easy Tune. But to answer the question.... I don't think so. The CPU is still pretty hot, even at idle. And stopping the fan could cause damage to the CPU. So no, it shouldn't stop the CPU fan at all.

**profJim** · 12-22-2010, 11:10 PM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

I've seen momentary 0 rpm readings on my systems when the AUTO setting is used for PWM fan headers. This might be caused when fans don't undervolt well with lowered voltage sent to the fan header. Some of the better 12 volt fans will still spin at low volts (below 5 volts) while lesser fans will stop spinning below ~ 7 volts.

I'd be surprised in your V8 cpu fan couldn't undervolt well without stopping. Double check the detailed V8 specs and see if it gives the voltage range of your fan.

Bottom line, don't worry, be happy.
The 0 rpm reading might be due to a sudden momentary increase in cpu activity.
The Sys_Fan2 header is another matter entirely, as it usually provides about 5 volts under normal conditions.

**bgarrant** · 12-22-2010, 11:39 PM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

Here is the V8 specs. Do you think it can go under 7V with SmartFan and cause it to stop? I see the V8 starts at 7V. Is this the issue?

V8 - Cooler Master - Leading Provider of Computer Case | Cooler | Power Supply

**profJim** · 12-23-2010, 12:06 AM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

The CM web site features picture states that the included manual fan speed controller can vary the fan's voltage from 7 - 12 volts, so your assumption is valid.

However, the cpu fan would have to stop completely before the minimum voltage spec would affect the fan. Given that the fan rpm display is zero for only one second, I doubt that the fan actually stopped and then restarted.

My preference is to use manual fan speed controllers, where I set the fan speed to just barely audible. If/when I'm using my system where I know that cpu temps will be much higher, I temporarily set the fan controller to a higher fan speed setting. In the bios PC Health section, I've set 60 (C) as the cpu alarm warning temperature. In order to hear the cpu alarm, you must have a case speaker connected to your motherboard.

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**bgarrant** · 12-23-2010, 08:41 AM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

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?

**carson** · 12-23-2010, 09:13 AM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

I've seen it happen a few times with HWmonitor. One time when it happened I took off the side of the case and watched the cpu fan and HWmonitor at the same time and while it reported zero rpm, there was no visible change in the fan speed. No stopping and restarting. I assumed it was a software issue.

**bgarrant** · 12-23-2010, 09:29 AM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

I thought so as well. I also had it happen with EasyTune6 a couple times. It is literally a seconds at most and then speed is reported at full again. I would think the fan could not even do an instant on/off anyway and RPMs would be visable during the change.

The CPU Fan alarm would sounds in BIOS if it ever stopped since I have it enabled correct? I also DO have a speaker setup for beeps.

**Lsdmeasap** · 12-23-2010, 12:15 PM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

Does it do the same if you use Voltage setting instead of PWM?

Are you using the latest BIOS?

**bgarrant** · 12-23-2010, 03:37 PM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

I do have the latest FD version of BIOS. I did notr try Voltage in BIOS for SmartFan control. I tried AUTO and PWM. SInce I have a V8 Cooler, should I use Voltage?

**Lsdmeasap** · 12-23-2010, 03:40 PM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

Try voltage and see if it acts the same.

Latest BIOS is FE1

http://download.gigabyte.us/FileList/BIOS/mb_bios_ga-x58a-ud3r_2.x_fe1.exe

**Psycho101** · 12-23-2010, 08:55 PM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

You haven't said if you've actually opened the case and looked at the fan in question. This is the most logical thing to do surely? Then you can establish if the fan is really stationary. If it isn't stopped when the RPM readout displays 0 then you can simply ignore it.

Any issues a fan being controlled by PWM will have are not due to low voltage. a PWM controlled fan receives pulses of full 12V. Also a 120mm fan absolutly will not stop at just under 7V regardless of brand. Every 120mm fan you will ever encounter will safely run when severely undervolted, even down to 5V which is the lowest I'd recommend going. There IS a minimum voltage required by a fan for it to initially start to spin, and this WILL vary depending on the model of fan. Conversely, even though a fan will refuse to start on for example, 3.3V, after initially being spun up on a higher voltage it may be then possible to drop voltage below 3.3V and still have the fan spin.

**sygnus21** · 12-23-2010, 09:36 PM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

You can use voltage as the 2nd pin on the CPU header is a +12v pin allowing the voltage to vary according to temps. In short it'll act like a PWM signal. I'm sure someone will clean up what I've said, but that's basically how "smart fan" works. And for what it's worth, that's exactly how my 3-pin Noctua fan is working on that header.

Good luck.

**bgarrant** · 12-24-2010, 03:55 AM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

I can't reaLly see the fan on the V8 cooler as it is between the fins. It does sound like it is spinning. I did crank it to full speed by disabling SmartFan in EasyTune6 and I can hear it spin without stopping, even though software show it show to 198 rpms. At full speed it runs 2000rpms.

**Psycho101** · 12-24-2010, 10:44 AM

Re: Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

It can be hard to tell at low RPM, especially if the fan s in the middle of the heat sink. Using something soft, such as a twisted piece of kitchen roll/loo paper, you can push it through the fins into the fan. Something so soft won't damage it, but it will give you tactile feedback on if the fan was spinning.

Note that at very low RPM, stopping a fan CAN mean it won't restart, but usually if PWM is used it will, it's usually voltage controlled ones that will stay stopped (due to a lower than start up voltage being applied, as I mentioned).

If it was spinning then you can safely say PWM is doing its job. However you can try voltage control if you wish, it's up to you of course.

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Can Smart Fan control stop CPU Fan at Low Temp or IDLE?

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