The PWM tachometer signal most probably have really good noise immunity as timing is robust against noise. Might also have really good accuracy if derived from a clock with low jitter and slow enough clock drift. However very unlikely to make any noticeable difference on a fan.
Once asked for external availability of PWM signal on measurement instrument as I could see it was used internally in datasheet/manual for data transmission over an isolation barrier and they might have listened as I have seen it is available in some now though I did not yet have any use of it, have used the analog signal with more or less noise. > With a 3-wire fan there are two power wires and the third is a tachometer. > Fan speed is controlled by varying the volts (or duty cycle) on the > power wires. > > With a 4-wire fan all thee above wires do the same thing but wire #4 is a > speed control signal that is PWM. This saves the need to PWM the power. > > On Tue, Dec 10, 2019 at 4:16 AM Gene Heskett <[email protected]> wrote: > > > Greetings all; > > > > I am running the stretch iso install here on this big house box, but > > since the fire destroyed the old Asus board, I now have a new Prime > > Z370-A ll, with a 9nth gen 6 core i5 running at 3.7GHz and 32G of ddr4 > > memory. Much quicker than the old 2.1GHz 4 core phenom. Pretty quick > > now. > > > > But the cpu fan I put in, a monster cooler-master, has the new 4 wire > > control, and is working very well, but is not reporting its speed. > > A run of sensors-detect only found coretemp and once modprobed, thats > > working well. Showing the max temps in the 29C range. Its a BIG cooler > > and I can't feel any heat at its base, so big I can't put the towers > > side panel on as it (the coolers heat pipes and radiator) is about 1/2" > > too tall. Shrug, its been off for 12 years now ;-) > > > > Does anyone else have any experience with these newer 4 wire fans? > > > > Thanks all. > > > > Cheers, Gene Heskett > > -- > > "There are four boxes to be used in defense of liberty: > > soap, ballot, jury, and ammo. Please use in that order." > > -Ed Howdershelt (Author) > > If we desire respect for the law, we must first make the law respectable. > > - Louis D. Brandeis > > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > -- > > Chris Albertson > Redondo Beach, California > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
