Question CPU fan running at max speed at all times. Lenovo ThinkCentre M91p

Jul 1, 2019
I migrated a SFF ThinkCentre M91p motherboard to a larger case so that I could fit a graphics card.

Specs in new tower:
Windows 10 Pro 64-bit
Lenovo IS6XM Rev. 1.0 motherboard
Intel Core i5-2400 CPU @ 3.1GHz
NVIDIA GeForce GTX 650 (graphics card)
128GB Samsung SSD
250GB Hitatchi HDD
Sparkle Power 550W Power Supply (previously 240W power supply in SFF case) Model FSP550-60PLG

Installed 2nd fan on back of tower case.

What I've tried:

-Isolating noise from fans (CPU is definitely the loudest and source of this post)
-Tried unplugging graphics card, extra fan, front fan - to no avail
-Tried SpeedFan software. Does not recognize motherboard or register fans.

What I haven't tried:
-installing a different power supply (I don't see how this could help, but who knows, that's why I'm here)

What I know:
-CPU is not overheating. Temp is normal.
-PC runs just fine despite the fan running at max speed. Games, general use, etc.

Any suggestions? More info needed?


Jul 11, 2018
You say temps are normal, however normal is different to every person. So what is the temperature of the CPU in Celsius when you are gaming AND when it is idle?

I would try to go into the BIOS on your motherboard and try to set a fan profile if your motherboard supports it. If that does not work, I would re apply the thermal paste on the CPU and ensure that the CPU cooler is properly attached to the motherboard. If that does not work, I would switch out the cooler for a Hyper 212 evo or something like that. The power supply looks like a cheapo power supply so I would swap that out with an 80+ bronze/gold power supply

Honestly, what I would recommend instead of all that is migrating to a newer Zen+, Zen 2, or Coffee lake refresh system. The YouTuber TechDeals makes computers, explains the thought process, why parts are what they are, etc. What are you using your computer for?
Jul 1, 2019
Idle it is 35 C. The thing is, it's running at max speed at idle upon start up. Anything I am doing on the computer, the speed doesn't change.

I am just experimenting with what I can upgrade this M91p to, with some parts I have laying around. I have a bunch of these towers at the moment (I refurbish and sell as a side hobby/income) and time to spare, so I'm not really using it for anything aside from a test machine. The intent is to run the video card and sell as a machine that can, for example, have a nice smooth experience playing Left 4 Dead 2 or CS GO, etc. That's about it. I'm not too interested in upgrading the CPU unless I come across one in a trade or for a really good deal and even then it would just be to experiment further or build upon request from a client.

I'm mainly looking for advice on the cpu fan. In BIOS, there is no specific fan profile that I can identify, rather phrasing like "Intel Speedstep Technology," and "Turbo Mode" under CPU setup. I can list them all if that might help provide reference.