a Mhz is a Mhz... its an internationally accepted and defined standard of measurement.
1Mhz = 1 million cycles per second, with 1 second being precisely 9,192,631,770 cycles of the radiation produced by the transition
between two levels of the cesium 133 atom.
as cpu designs, cache design, size, organisation, and efficiency are different this leads to different numbers of instructions being processed for each cycle, thus giving rise to differing levels of PERFORMANCE.
this can be crudely summarised to
Mhz X Instrucitons per second = performance.
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