Fan curve tuning for beginners

Blowsy · 18 Oct 2020 at 17:13

Evening all,

I need a bit of help.

Just finished building my first PC in over 15 years. I have a question regarding fan curves.

I'm running 3x 140mm front intake, 1x 140mm rear exhaust along with a top-mounted 360mm exhaust AIO.

MSI Tomahawk X570 motherboard, Ryzen 3600XT, and a 1650 Super GPU (until my 3090 pre-order arrives)

I downloaded MSI Dragon Center (what a piece of **** that is!) and ran through the "Smart Fan" tuning test which seems to have cocked things up. I'm now hearing the case fans spinning up and down during idle which is really annoying.

How should I be doing this? MSI Afterburner also has fan curve tuning, is this for GPU only, though?

I'm now a bit worried that I don't know which software is actually controlling the case fan curve.

I'm guessing I should be doing this in BIOS, but a software tool would be so much easier, surely?

Any beginners guides out there anyone could recommend?

Rom · 18 Oct 2020 at 21:19

Ive always used Bios for fans, and manually set them up. I dont care too much about noise, id rather have a steady hum, than sporadic jet engines.
So i generally have a steep curve, basically they will be at a set speed, unless things go nuts and they will ramp up.

Slinky69 · 19 Oct 2020 at 08:48

I found the fan curve in the MSI X570 Tomahawk BIOS a bit baffling at first, but once you've worked it out it's easy enough

bimbleuk · 19 Oct 2020 at 09:55

With 140mm front fans you could simply set them to a constant rpm that is acceptable audibly as they will shift a lot of air anyway. Rear 140 mm fan might benefit from running higher when the CPU/GPU are working so set it similarly to the CPU cooling fans - see below.

With my Ryzen R9 3900X I have the AIO (Kraken X62) fans linked to the CPU temp. I use CAM but could be BIOS or other software. They are constant ~50% at "idle" but at ~ 60 DegC they ramp almost straight up to a high fan speed say 70-80% but not too high or loud as you don't need it with a decent AIO.

Pump speed is set to ~50% at idle (assuming water temp stays constant) and again as the temp hits ~60 DegC it switches to 90% and runs constant.

More simply put to ignore the constant ramp of the Ryzen cores you set the trigger point for more cooling under load to when more then one core is genuinely loaded. If I could reference the average die temp it would be simpler but most BIOS/Software uses a single core reference. On the Ryzen CPUs that temp constant spikes as a core is woken to do some work.

My fans curves are simple stepped lines with an idle temp and a load temp. Some slope on the ramp point helps to smooth the fan ramping.

You can refine this process even further using the CTR Clock Tuning tool to even out the single core temp spikes but that's a whole over subject

doyll · 19 Oct 2020 at 11:41

Phanteks P500A w/ 3x 140mm front intake, 1x 140mm rear exhaust along with a top-mounted 360mm exhaust AIO. You will need to be careful or you could easily have more exhaust than intake and you end up with dust coming in other openings in case with dust collecting on things. Especially if 140mm intake fans are not running at same or similar speed to rad fans. 3x 140mm intakes have more airflow restriction from front grill and filter than rear and top grills without filters .. top vents with rad probably have similar airflow resistance as front grill and filter does. Grills restrict airflow by 30-69% depending on mesh / pattern plus another 30-50% airflow loss from filter. Links below are to grill and filter airflow restriction tests.
https://www.silverstonetek.com/techtalk_cont.php?tid=wh_chessis&area=usa
https://www.silverstonetek.com/techtalk_cont.php?area=ru&tid=wh12_008
https://www.pugetsystems.com/labs/articles/Effects-of-Grill-Patterns-on-Fan-Performance-Noise-107/

360mm rad with 3x 120mm fan moves at least as much air as 2x 140mm intakes at similar speed as 120mm rad fans should be okay. I would run rear fan at lower speed .. actually I wouldn't use any rear exhaust fan, but lest the force of intake fans push out additional airflow they are pushing case that top rad fans are not pulling out.

I've found motherboard fan software to generally be fine. Below is idea of how mine are set":

2x 140mm (PH-F140MP 500-1600rpm) intake fans in Entho mATX case with 3600 under ARO-M14O (w/ included TY-147A 300-1300rpm fan).

20% at 32c
40% at 60c
75% at 70c
100% at 75c

Above settings keep things silent most of the time unless I'm rendering graphics. Then I can occasionally hear fans, but that is with CPU load of 80-85% at 70c with fans at 900-1000rpm