> Variable speed fans are available now and motherboards support them. > Tachometer outputs have been around for a long time, and because fans > use brushless "DC" motors (i.e. synchronous motors with electronics to > generate the AC) they all have to have rotational phase detectors > (although it may be done by monitoring the coil current, rather than a > separate sensor). Heavy use of these tends to be associated with > "quiet > PCs", so the BIOS may well be set for minimal cooling, rather than > keeping a low temperature.
The biggest problem, IMHO, is that as soon as Windows boots up the fan speed goes to 1/2 to 1/4 of its previous speed, and Windows has no control, that I know of, to alter that behavior. Fans are cheap now. I set the BIOS for max fan speed and disable automatic control. This is a real issue for people who run SETI@Home. Since all of S@H's applications are heavily optimized, they use all the CPUs, all of the logic therein, all the time, and throw off huge numbers of BTUs. Charles Elliott > -----Original Message----- > From: questions-bounces+elliott.ch=comcast....@lists.ntp.org > [mailto:questions-bounces+elliott.ch=comcast....@lists.ntp.org] On > Behalf Of David Woolley > Sent: Tuesday, December 9, 2014 3:09 AM > To: questions@lists.ntp.org > Subject: Re: [ntp:questions] Red Hat vote for chrony > > On 09/12/14 07:06, Charles Swiger wrote: > > Yes, I also find it a bit surprising than modern desktop CPUs and > GPUs > > are willing to run right up to their thermal trip points of ~80 C or > so > > rather than bump up fan speed a little more to keep them more around > 50 C. > > Cost engineering, for what is a throwaway product with a fashion life > of > less than 3 years. Also, > > > > Older systems tended to use more aggressive cooling, especially > laptops. > > > > Well, smarter firmware and Hall effect sensors to measure fan speed > means > > you can spin the fans more slowly than if you needed to apply 40% > minimum > > speed just to be sure that the fan would spin up from idle. > > Variable speed fans are available now and motherboards support them. > Tachometer outputs have been around for a long time, and because fans > use brushless "DC" motors (i.e. synchronous motors with electronics to > generate the AC) they all have to have rotational phase detectors > (although it may be done by monitoring the coil current, rather than a > separate sensor). Heavy use of these tends to be associated with > "quiet > PCs", so the BIOS may well be set for minimal cooling, rather than > keeping a low temperature. > > _______________________________________________ > questions mailing list > questions@lists.ntp.org > http://lists.ntp.org/listinfo/questions _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
