Enigmatic8

I didn't change the text color, it was on default after I signed up. I just checked and it says it is on automatic. As stated in post, I have tried to vary the fan curves. None of them are steep. I have since this post turned off both system 2 fans, lowered my CPU fan to as much as it would let me (700rpm) and the same problem persists. I am going to need to remove the side panel and observe to determine which fans are speeding up. I suspect it is all of them and my theory of faulty temperature sensors is most likely.

Ever since I upgraded my mobo (early last year) I've had this strange issue I just cannot figure out. In games whenever I go into a menu or there is something like a loading screen, my fans (I think all of them, CPU and GPU included) rev up to 100% for a couple seconds and then stop. Example: The Witcher 3. After playing for a bit (and so PC is more warmed up) I go into the menu and the revving to 100% starts, then stops, and I can continue to look at inventory etc. On games like Yakuza 2 whenever there is a loading screen the same revving happens, then it stops (even if the loading screen is still going). My FPS is capped at 144fps (confirmed with steam fps counter and FRAPS) as I've heard 1000s of frames during menus/loading is possible and could be problematic. HWMonitor confirms temperatures for CPU and GPU are safe (well under 70c each). The odd thing is that the 100% rev does not register on HWMonitor or other software. If I alt-tab out and check, the max is still the same for that session (as does the before, during and after the revving reading on each fan remain unchanged). I have tried different custom fan curves but to not avail. No steep climbs, all steady. The only explanation I can come up with is that I've got faulty temp sensors on my mobo (Gigabyte Z370 - I've also upgraded to latest bios) which is causing them to give insanely high false temperature readings during places where, if not for the FPS cap, my GPU and CPU would be dealing with 1000s of frames (e.g. loading screens + menus). This in turn causes all my fans to max out 100%. This issue has plagued me through 3 different GPUs and 2 different CPUs and different RAM sticks. So I don't think they are the issue. I've reinstalled Windows 10 since this issue began, which hasn't helped at all. Has anyone got any experience with something like this or what the cause could be? (As an aside, I also earlier this year bought my 2070S Gigabyte card which has fan revving issues if you put it below 40rpm. Others online also appear to have this issue with this card from Gigabyte. My mobo is, as above, also Gigabyte... which I don't believe to be a coincidence if it is causing my fan problems generally.)