Hello all! There was a recent interesting development with my custom build. The CPU fan is the only fan in the case. I have some variant of the Cooler Master Hyper series 120mm PWM (4 PIN) currently. One day recently, I powered on the computer. I could hear the normal process of boot up (fan speeds up, and then it gradually slows down to normal operating speed, 2800 RPMs or so). However, this time the fan speed kept dropping (noticeable audibly, because typically it was loud) and SpeedFan showed 1043 RPMs. Also, CoreTemp typically reports processor temperature around 30 degrees Celsius, never higher than 35 degrees. As the fan speed has dropped, and it never speeds up, the temperature now stays steady between 47 degrees and 55 degrees, depending on activity. I confirmed all of these findings in the BIOS. I replaced the CPU cooler and fan in 2014 with the current unit, because of the exact same issue. Every component of the computer is the same, nothing has changed hardware or software wise. Obviously, the motherboard is aging. I'm mostly curious I suppose as to what I should do next. I've exhausted researching forums, and done some troubleshooting steps to no avail. I have noticed no differences in terms of performance. I don't know if this a motherboard issue or another bad fan. Motherboard is the Asus M4A785-M. Processor is the AMD Phenom X4 9550. Thanks in advance for your help.