weird heatsink PWM fan behaviour

[Nine Iron]

Just got hold of a new CPU cooler - NT07-115x, for reference - and it's behaving oddly.

I plugged it into the CPU fan header with the min. speed set at 12.5% in the BIOS (target temp <70 degrees), and the thing blows a gale - 2000+ rpm. I then tried it in the 4-pin SYSFAN header, and it works pretty much as it should. Indeed, in Speedfan I can put the speed wherever I want, and it stops below 30%. (One thing I did note, though, is that there is a very sharp increase in RPM over a small power interval - quiet at 60%, then RPM doubles at 65%.)

This issue does not affect my current heatsink; that one will sit at 700 RPM all day in the CPUFAN header. Any ideas? It's far too loud to run at "idle" as it is, but I would consider adding a discreet speed reducer.

 

[tolagarf]

Sounds like you have a MSI motherboard? Anyway in that case, target temp as far as I can gather from working with these boards is the temperature at which your fan should speed up. So setting it to 70 degrees might be a bit crazy. I would set it at 45 or so.

You probably need to experiment with it, but if you're using Speedfan I would dare say you should leave the CPU fan speed on Auto in the BIOS, else the software and BIOS might conflict in controlling your fan speed.

 

[Nine Iron]

Sounds like you have a MSI motherboard? Anyway in that case, target temp as far as I can gather from working with these boards is the temperature at which your fan should speed up. So setting it to 70 degrees might be a bit crazy. I would set it at 45 or so.

You probably need to experiment with it, but if you're using Speedfan I would dare say you should leave the CPU fan speed on Auto in the BIOS, else the software and BIOS might conflict in controlling your fan speed.

I only installed Speedfan after the first attempt at getting the heatsink working, so there wouldn't be any conflict.

And yes, it's an MSI board - I thought the target temp was the temp under which the CPU is intended to be kept...