There are cycles per second aka MHZ and there are instructions per cycle... do you have an Athlon XP? It is much more efficient than the Pentum 4. An Athlon XP running at 1.57 GHZ out preforms a Pentium 4 2.0 GHZ. It is more efficient at using those cycles and therefore is faster. The modified IBM chip is much more efficient than the CELERON processor in the X-Box. Almost twice as efficient in fact. MHZ mean nothing these days without other things involved.