cyclebabble
cyclebabble
(jargon)IBM uses raw clock speed as the speed of the computer. Inthe IBM PC and IBM PC XT, the clock is divided by 4 toproduce the 4-phase bus clocks. Thus a 4 MHz IBM XT reallyruns at 0.895 MHz, because that 4 MHz was really 3.58 MHzwhich gets divided by four.
A Tandy Color Computer ran at exactly the same speed, butclock speed was specified as bus speed, 0.895 MHz, leaving theimpression that it was 4 times slower. Actually it ran alittle faster with a more efficient instruction set. If theactual clock rate had been specified on a CoCo 3, it wouldhave been 14.32 MHz, although the bus speed was still 0.895MHz. That high speed also generated video, color, and hidden refresh timing.
100 MHz computers are running at bus speeds of around 25 MHz.