I wonder if the case fan(s) is(are) getting the PWM output signal properly. I wonder if you are trying to use a 3-wire non-PWM-compatible case fan, for some reason, are are using incompatible adapter(s)/splitter(s) or have the adapter(s)/splitter(s) connected incorrectly.
Please tell us about the fan(s?), how it(they?) are connected, and about any adapter(s?) and/or splitter(s?) you are using. It looks like a simple incompatibility or wiring/connection issue. Give us the manufacturer name, part number, and/or model of every fan, splitter, and/or adapter used. Bonus points for Amazon links and a hand-drawn sketch of your fan wiring.
For it to work properly, these are the important aspects:
1) The fan(s) and all adapters/splitters must be 4-pin 4-wire PWM compatible.
2) If powering more than one fan, the fans must get their power and ground("negative") from the power supply SATA or Molex connector directly, and NOT from the video card directly if their total peak current consumption is anywhere close to 1 amp.
3) If powering more than one fan, the splitters used must provide the PWM signal to all fans, but it must be that ONLY ONE fan's tachometer feedback gets back to the video card. If you used multiple stacked ("daisy-chained") splitters, you will need to cut any redundant tachometer feedback wires, or make sure the additional daisy-chained splitters daisy-chain off of one of the root splitter's headers which doesn't have a tachometer feedback wire connected.
post edited by ty_ger07 - 2019/02/16 14:29:21