Find the cause before replacing parts
Record what changed, make one supported change at a time, and keep a way back.
Choose an observable symptom
Keep the starting state
Record the application or game version, settings, driver version, recent hardware changes and the circumstances that reproduce the issue. Compare the same scene and workload after each change. A single utilization reading cannot diagnose every constraint.
Use official drivers and exact support manuals. Never open a power supply, reuse undocumented modular cables, or use unofficial firmware and automatic driver-updater utilities.