Computer clock speed has been roughly doubling every year. The Intel 8088, common in computers around the year 1990, ran at 4.77 MHz. Today's computers run at several hundred megahertz. If you double the speed of the clock, leaving all other hardware unchanged, you will not necessarily double the processing speed. The type of microprocessor, the bus architecture, and the nature of the instruction set all make a difference.
Some processors execute only one instruction per clock pulse.
More advanced processors can perform more than one instruction per clock pulse. The latter type of processor will work faster at a given clock speed than the former type. Excessive clock speed can be detrimental to the operation of a computer. As the clock speed in a computer rises without upgrades in any of the other components, a point will be reached beyond which a further increase in frequency will render the processor unstable. Some computer users deliberately increase the clock speed, hoping this alone will result in a proportional improvement in performance, and are disappointed when things don't work out that way.