Case Fans Acting Weird

So the case fans on my system are a bit strange, they're both set with the exact same fan curve, both are PWM and are set to base their speed off of the CPU temps. When I first built the system, I knew I already had a bad fan header, because anything plugged into it was given max power with no way to adjust it, so I knew there was a bad pin, no biggie because I had two more headers, and I only planned on using 4 case fans, so with 2 splitters that issue was solved easily without need for an RMA.

However, with both being set for the exact same fan curve, you would imagine, based on CPU temps, that they'd hover around the same exact RPM and be synced together in a way, sometimes they'll heavily vary though, and every now and then, one of the fan sets will just jump out of nowhere to sometimes double what the other fan set stays at, and it'll stay there regardless of CPU temp, and the only fix is to shut it off and turn it back on, actually clicking restart makes the issue persist so it has to be a full shutdown when that happens.

But when the one set randomly jumps to a high RPM, the other set stays where it's at, and it's not just one set, either or can do this, and I know it's not a hardware issue because of that, and the fact that this is a semi-rare thing, when it does happen, it'll happen 2 or 3 times tops during that day, but then I can go days without it happening, sop I'm thinking it's the BIOS itself, but this issue has happened since day 1, and I've updated the BIOS multiple times with no changes to this issue, any ideas?

I'll post two pics from my system meter to show how much they can vary, one picture is from when it happened under Idle, one of the sets of fans was running around 350RPM, and my other set randomly jumped to over 1000 for no reason at all, and the second image was grabbed while the system was under load, one set of fans stayed at around 1300 which is where they both were, until one jumped up to 1700RPM randomly, it's just such a strange issue so I was hoping someone might have some insights into it, or maybe experienced a similar issue?

Windows version is 1903 (OS Build 18362.657)

Does the BIOS of this mainboard also provide fan speed settings that could be interfering with your software settings?

Rkdl said:

Does the BIOS of this mainboard also provide fan speed settings that could be interfering with your software settings?

That's the thing, I don't have any other software to control fans, I've always let the BIOS sort those out with the PWM settings, I apologize if I made it seem like I had other software, but the software I was referring to is the BIOS itself lol, the only thing controlling the fans is that, but after updating it multiple times to attempt to fix this issue, every new one that's released I update to it, hoping they've found and fixed this issue, but I've had no such luck, I've never had this issue with any other board though so I'm at a loss on where I should actually be searching for a cause

Perhaps set BIOS defaults then remake you fan settings?