HP 8300 Elite SFF: Is PWM Supported on this board?

[Red5_1]

Is there something I am missing to get PWM working?

I recently picked up an 8300 Elite SFF and decided to replace the old front fan with a new 4-pin PWM fan. The new fan says it has a range of 800 to 2800 RPM. When I performed a stress test, after 30 seconds, the temperature of the CPU rose to almost 80 degrees and the fan speed didn't change one bit. I let it run for about a minute before ending the test. I have the fan plugged into the CHFan header (which is the appropriate header for the CPU fan).

I upgraded the bios to 3.07 hoping a new feature would appear, but the only option I noticed there was the ability to set the minimum speed of the fan headers to 5 various speeds (I assume 20%, 40%, etc up to 100%).  As a test I set the minimum speed to max. When the PC booted, the fans did run full speed and were "jet engine" loud. I ran another stress test for 5 minutes at that point and the temps stayed under 65 degrees.

I had always assumed that a 4-pin header meant that PWM was supported. Maybe that was a poor assumption...

Here is a link to the board: http://h10032.www1.hp.com/ctg/Manual/c03612803

Anyone have any ideas or suggestions?

[Red5_1]

Nudge. Hoping someone with strong knowledge of these boxes or PWM can comment.

[Red5_1]

Another nudge.

[DGroves]

while it's normal for the fan to ramp up in speed during power on it should spin down within 5-9 seconds

if it stays full speed then you may have the wrong fan connected, or the cpu heatsink  is not properly mounted these are two of the most common reasions for a fast fan speed

https://www.amazon.com/Foxconn-PVA092G12H-4-Pin-Fan-HP/dp/B00H0B4I9G

https://support.hp.com/us-en/document/c03343457

[Red5_1]

I have the original fans that came with the PC. That Foxconn you mentioned is the CPU fan and there is an ADDA-brand fan in the PSU.

There is a setting in the BIOS that allows you to set the minimum speed of the fan. The CPU  fan appears to always run at the speed as determined by that BIOS setting. The expected speed up at boot does not occur, nor does it ramp up the speed during stress tests that send the temps around 80 degrees.

I tried a different non-Foxconn 4-pin fan on the CPU header with the same results...which is why I am beginning to wonder if this board actually supports PWM in the first place despite the headers being 4-pin. This is the first time I have run across a 4-pin header that did not regulate the fan speed (with no settings in the BIOS).

Any additional thoughts are appreciated.