I have a D2500CC board running the latest kernel of ArchLinux x86_64. The system is used as a 2 port firewall. I do not use 2D or 3D graphics, just Console output, SSH, and Apache for outputing various bits of info.
Both applications use underlying tools like "smartmontools", "hddtemp", and "lm_sensors" (along with other underlying tools) to monitor various aspects of the system.
I have successfully configured "lm_sensors" to monitor the Winbond W83627UHG chip on the board. This chip is supported in the version of "lm_sensors" that I am using.
I have noticed in Systemgraph, Webmin, and on the Console (using the "sensors" command) that fan speed output occasionally registers as "zero" even though I can visibly see the fan turning.
I have tried 3 different models of 3-pin fans including one that has not reported any issues when connected to another vendor's board. I have tried connecting the 3-pin fans to the motherboard 3-pin connector. I have tried an adaptor cable that only connects the fan speed sensor wire to the motherboard connector and pulls fan power from a 4-pin Molex plug (the same type and style used on older model hard drives). I have verified these fans do not pull excessive amounts of power; a maximum of 0.028 Amps and 0.34 Watts in one fan test case, slightly more in the other 2 test cases.
BIOS: Latest "034" version published in June 2012 by Intel
BIOS setup for fan: "Manual"; "Under-Speed Threshold" set to 500; no other fan settings are available
Note: I changed the fan settings in the BIOS because the default BIOS settings for the fan had it spinning at 500 to 600 rpm and that did not circulate enough air within the chassis to adequately cool the hard drive. Hard drive temps of 40 Celsius were not uncommon with the default BIOS setting for the fan. With BIOS settings for the fan set to "manual" the fan will spin at 2000 rpm +/- 10% (the rated speed for the fan) and the hard drive temperature stays between 30 and 33 Celsius all the time (good air circulation). Hard drive temps were measured using "smartmontools" and "hddtemp" The hard disk is a Western Digital Black 320G laptop (2.5 inch form factor) SATA drive.
I have used other boards from other vendors that use the Winbond W83627DHG series monitoring chips. I have never seen this behavior before on those boards with those different model Winbond chips.
So the questions I have are this:
(1) Why does this fan sensor occasionally send a "zero" reading to the "sensors" program that reads the chip registers?
(2) Does anyone know if this behavior is normal for this Winbond W83627UHG monitoring chip?
(3) Has anyone else noticed this problem on this board?
(4) Has Intel registered any customer reports of this problem?
(5) Does anyone at Intel think this problem may be corrected in a future BIOS update?
(6) Does Intel this this board is defective in any way that would justify warranty replacement?
In my case this board is less than 1 month old and "behaving badly" compared to competitors.