After migrating a guess to a similar (but not the same CPU) the messages appear in the logs:
Clocksource tsc unstable (delta = 125002555 ns). Enable clocksource failover by adding clocksource_failover kernel parameter.
The kernel attempts to keep some kind of consistency in regards to clock migration, the underlying hardware watchdog seems to iterate through all of the available watchdogs/clocks. I don't know if you know how to read code, so I'll attempt to explain what is happening
The kernel implements some kind of clock watchdog to ensure clock sanity for process accounting and that the clock behavior is generally consistent.
My comments relevant to the discussion are in these style delimiters */ */ , and this is a modified version of the source code cut back for easier understanding.