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1000rpm slowest speed for Intel fan?

Posted: Sat Oct 20, 2012 8:57 pm
by Luke M
I'm using an Asus Z77-V LK and can't get the CPU fan (standard Intel) to run slower than 1000rpm. Is this a limitation of the Intel fan or the motherboard? I assume the motherboard is using PWM control (there's no option).

Speedfan doesn't work with this motherboard.

Re: 1000rpm slowest speed for Intel fan?

Posted: Sat Oct 20, 2012 10:31 pm
by lodestar
It's a limitation of the fan. Typically Intel stock fans run between about 1000 rpm to 2000 rpm. As you have an Asus motherboard the way to minimize stock fan noise is to set Q-Fan control to Enabled in the Monitor section of the BIOS and select Silent for the CPU Fan profile. The Silent profile will keep the speed down to the 1000 rpm end of the range until the CPU hits around 40C. If you are using Windows and want to see what the Silent profile is doing download the latest version of AI Suite II from the Asus website. AI Suite II includes Fan Xpert+. Fan Xpert+ will give a graphic display of the current fan profile. It can be used to change the BIOS CPU Fan profile without rebooting the system, and allows the option of a User profile where the fan control parameters can be set manually.

Re: 1000rpm slowest speed for Intel fan?

Posted: Sun Oct 21, 2012 5:37 am
by benius
lodestar wrote:It's a limitation of the fan.
I wouldn't be so sure.

Image

Read this: http://www.silentpcreview.com/SpeedFan (if you didn't already).

But why do you want to run it below 1000 rpm, anyway? In my experience, at that speed the fan it's virtually inaudible.

Re: 1000rpm slowest speed for Intel fan?

Posted: Sun Oct 21, 2012 5:57 am
by lodestar
It's still a limitation of the fan, at least this particular fan. The Asus BIOS CPU Fan Silent profile runs the fan in the 20% - 100% duty cycle range. At the 20% end with fans capable of going down to 300 rpm then you might well see actual idle speeds around this level. But most Intel stock fans have the minimum rpm set at around 1000 for the 0 to 20/30% duty cycle settings. Using Asus Fan Xpert+ the CPU fan can be calibrated to show the fan rpm for the 20% to 100% points; this will establish exactly what the minimum potential rpm is.

Re: 1000rpm slowest speed for Intel fan?

Posted: Sun Oct 21, 2012 3:12 pm
by Luke M
Thanks for the info lodestar. The Intel fan speed range is (according to the Asus fanxpert+ utility) 1000-2000rpm. In other words, the minimum speed is 50% of maximum.

Probably you could go lower with undervolting, but I couldn't find any way to manually select voltage control. Apparently, the motherboard automatically selects between PWM control or voltage control based on the fan type (all the fan headers are 4-pin, but 3-pin fans work with speed control).