Question CPU Fan issues/question


Jan 14, 2017

I am having some heat issues in my desktop build.

Upon boot, I get a CPU Fan error which loads me directly into the BIOS. There I either see that the Fan is running "in the red" (lower speed than the BIOS likes) OR is shown as not detected.

I can hear the fan spinning while this is happening and if I bypass the bios and get to the desktop, after loading up CPUID HWMonitor, it shows that there is a fan speed detected.

I guess my concern is I am not sure if this is a fan problem, a connection problem (was going to check that after posting this thread), or a motherboard problem. I am really hoping it is one of the two former.

It may also help to know that this build is 5 going on 6 years old, not sure how much of a factor that may bring.

AMD FX-8350
Asus - M5A99FX PRO R2.0 ATX AM3+
CM 212 Hyper Evo

Thanks for any help I may get.
It is possible that you are dealing with a fan with badly worn bearings that is slow to start up. But it's also possible that you fan is designed to run more slowly than some and still deliver lots or air. In that case, you can change a BIOS Setup setting to match your fan's characteristics. See you mobo manual p. 3-28, "CPU Fan Speed Low Limit". Its default setting is 600 rpm, but if that is not what it really is set to, you can change it.

I note that the specs of your CM 212 Hyper Evo CPU cooler system says the minimum speed of its fan is 600 RPM, so having the BIOS low speed alarm set to 600 RPM would be right. If the fan really IS running slower than that, it may stall. Then it will remain stalled until the CPU_FAN header pushes its speed signal higher to get it to re-start, and that can take a minute or so. During that time, no doubt the system WILL send you an alarm that the CPU cooler is not working! But if that really is what is happening, then yes, your fan probably is worn out and needs replacement. OR, IF you set up some custom fan "curve" that tells it to run slower than 600 RPM when the system is cold, you need to change that lower setting.