Dell C6100 - Fans start out quiet, but over time grow louder


New Member
Dec 1, 2018
Hey everyone,

This isn't your usual "holy cow the C6100 is noisy!" question. My Intel (Tyan XS23-TY3) C6100 (after its initial jet engine startup) is actually rather quiet, likely because I am not pushing it too hard very often. I'm only running 2/4 blades as well, and they're located in the bottom-left and upper-right slots. The other two slots have blades in them, but they're pulled out just a bit so they're unplugged.

My temperatures are all good (21c ambient, CPU temps under 55C, MB temps 50C), but as I type this right now my fans are steady at 5100rpm. They usually idle quite a bit lower than that (to the point where it's barely noticeable).

I did try playing with the thresholds but there was no change in their speed. If I power cycle the chassis right now they'll idle down to that nice super quiet speed again so I know that they aren't needed to run this fast, yet I'm not sure how to get the chassis to knock them back down in speed.

I'm running v1.33 of the IPMI firmware on one, and 1.28 on the other. I'm reluctant to play with firmware upgrades because a) I'm a little nervous about screwing it up, b) I don't know which firmware files are compatible with my hardware and c) the system has been running reliably for over a year.

There's nothing interesting in the SEL; the fru and dcmi sensor info matches the "sensor" output.

Does anyone know how to kick the fan controllers to get them doing their job a little better? How do fan thresholds from the (up to) four management engines get combined and ultimately control the fan controllers?