Skylake and newer Intel CPUs do not need to have the timer enabled as they are RTC bug free.
However we have seen some "bugged" subs with an error (regarding HPET timer) in X265. (with a Coffeelake CPU and a Server OS).
The creator of X265 says there is sometimes a detection issue with some server OSses ( probably due to lite versions ) and it is recommended in case X265 gives an error to enable the HPET timer and re-run.