From the article I think that's backward. AMD's RDTSC is a constant-rate cycle counter and APERF counts actual cycles. So with clock boosting from XFR, etc, APE

From the article I think that's backward. AMD's RDTSC is a constant-rate cycle counter and APERF counts actual cycles. So with clock boosting from XFR, etc, APERF will increase while RDTSC will not.