Power
The source must cover the exact documented current and connector path.
Before GPU load
Setting up.
RPM up?
Record two settings your exact controller already showed. See whether the reported RPM moved the same way.
No wiring recipe. No controller, electrical, safety, airflow, or cooling approval.
Owner observation
Did it respond?
Use readings you already observed in the controller test or before GPU load. Do not lower required cooling to create a receipt.
Runs here. Nothing is uploaded.
Exact manual first
Fan power and control are separate.
Control
Requested setting and tach reading must come from the same documented controller.
Load
A response receipt still does not prove airflow through a GPU.
ARCTIC's exact S12038-8K manual documents PWM control and a 3.2A header warning. Its specification sheet identifies the 4-pin tachometer and PWM signals. Those facts do not approve another fan, header, cable, or controller.
Response recorded?
Open the first-load cardWatch the first load.
Keep the fan operating and follow the exact hardware instructions. Stop for any physical, electrical, fan, airflow, or rising-temperature problem. Comparing two stable setups? Build a Quiet Rig receipt.