Hi folks,

My Gigabyte EX58-extreme is still well and kicking after pulling 3 years of homelab ESXi server duty. It's now migrated to my workstation but I have an annoying problem with the CPU fan. System specs:

  1. EX58-Extreme mobo
  2. Xeon X5670 CPU (formerly i7 920)
  3. 6x 4GB Kingston HyperX 1600 RAM

Here's the situation, when I first got the system up and running with the Xeon chip, everything was good, temperatures were cool, fan speeds low. Core temps around 35C Prime95, this is with a Zalman CPNS14X cooler.

I know the chip is good for 4.2Ghz @ 1.25 vCore (ran it on my eVGA beforehand for 3 months) so I dialed in those basic settings and off we went. Temperatures were still very good, < 50C on all cores Prime95 but the CPU fan would spin at full speed regardless of core temps.
The fan hooked up is a 4pin PWM fan and I've tried changing the bios fan control settings from auto, to pwm, to voltage but nothing works, the fan just keeps spinning full speed from POST onwards.

Any ideas?