Intel® Pentium® Silver and Intel® Celeron® Processors Datasheet, Volume 1
The timers are accurate over any 1-ms period to within 0.05% of the time specified in the timer resolution fields.
Within any 100-microsecond period, the timer reports a time that is up to two ticks too early or too late. Each tick is less than or equal to 100 ns; thus, this represents an error of less than 0.2%.
The timer is monotonic. It does not return the same value on two consecutive reads (unless the counter has rolled over and reached the same value).
The main counter uses the PCH’s XTAL as its clock. The accuracy of the main counter is as accurate as the crystal that is used in the system.The XTAL clock frequency is determined by the pin strap that is sampled on PMC_RSMRST_N.