TIME is king. Smaller time wins.  "n× faster" = Time_slow / Time_fast.

MASTER:  CPU time = IC × CPI × T   =   (IC × CPI) / clock rate
         Total cycles = IC × CPI
         T = 1/F ,  F = 1/clock rate      (GHz → divide, ps/ns → multiply)

AVG CPI: counts       → Σ(CPIi·Ci) / ΣCi
         percentages  → Σ(fraction · CPI)

COMPARE: same ISA  → IC cancels
         same machine → T cancels, compare total cycles

MIPS = IC / (time × 10⁶).   TRAP: high MIPS can be SLOWER. Trust time.

AMDAHL:  New time = Unaffected + Affected / r ;   Speedup = Old / New
         Max speedup = Old / Unaffected.   Target < Unaffected ⇒ IMPOSSIBLE.

UNITS:   ps=10⁻¹²  ns=10⁻⁹  µs=10⁻⁶  ms=10⁻³  MHz=10⁶  GHz=10⁹