A server administrator receives reports that a production server is shutting down unexpectedly after running for several hours. The server is a 2U rackmount unit located in a data center with proper ambient cooling (20°C/68°F). The server has redundant power supplies connected to separate PDUs and no power anomalies are reported. The administrator checks the operating system event logs and finds a critical log entry: 'The system was shut down due to a thermal event.' However, the CPU temperature logs show that the CPU was at 47°C at the time of shutdown, and the chassis inlet temperature was 23°C. The server's internal fans are running at high speed and are clearly audible. The administrator suspects a thermal issue but is unsure why the CPU is not showing high temperature. The server has a baseboard management controller (BMC) that monitors various sensors. Which of the following components should the administrator investigate FIRST to identify the likely cause of the shutdown?