The thermal compound is in place, and I have attempted swapping the CPU two times - both times, the thermal compound had spread properly from the downward force of the heatsink. As such, the heatsink appears to be fitting tightly. It is also well within the specifications for the wattage of these CPUs.
The fan seems to be running well enough through the Dell Diag - the system is fully capable of controlling the speed of the fan, and the fan reacts accordingly.
Something is just not telling it to slow down during normal operation. The fan isn't running fast in reaction to something, like the CPU immediately gets hot and it's trying to cool it down - it just starts up fast from boot and never slows. The idle temp on the Sempron that's in there right now is ~34 C.
At this point, the only thing I can think to do is just splice the board connection onto a slower, quieter fan and run it that way. I know this fan was meant for BTX setups, but it's just not working right, and is completely unusable as-is in an office environment.
