~MHz registry value and TSC

Exploring Win2k kernel, I see that the ~MHz registry value is taken
from Prcb->MHz. In turn, Prcb->MHz represent a TSC frequency if the
processor has RDTSC instruction.

Can I rely upon that the ~MHz value represent TSC frequency in all
Windows versions starting from Win2k and with all HALs? Of course, if
RDTSC is supported by the CPU.