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What Is GHz (gigahertz) in Computer Processor?


 One of the most common indicators of CPU performance is a given chip speed in GHz (gigahertz) of the computer processor. Computer processors with higher GHz ratings can theoretically do more in a given unit of time than computer processors with lower GHz (gigahertz) ratings. 


However, the speed rating of the processor is just one of the many factors that affect the speed that it actually processes data. 

Given that some special applications can be very computationally demanding choosing the fastest computer is more important than buying a PC with the highest clock speed.


System Clocks

Computer processors work according to a clock that beats a fixed number of times per second usually measured in GHz (gigahertz). For example, a 3.1 GHz processor has a clock that beats 3.1 billion times per second. 


Each clock beat is an opportunity for the processor to manipulate several bits corresponding to its capacity – 64-bit processors can work on 64 bits at a time while 32-bit processors work on 32 bits at a time.


Internal Vs. External

The clock that is usually included in the marketing materials is the internal clock but the processor also has an external clock that determines how fast the processor can communicate with the outside world. 


The internal clock represents the speed at which the processor can manipulate the data it already has while the external clock indicates how fast it can read the information it needs to manipulate or how fast it can produce the manipulative data. 

As of the date of publication, external clocks are often significantly slower than internal clocks. 


For example, while a computer processor (CPU) may run at 3 GHz (gigahertz) its external clock can be between several hundred MHz and 1 GHz (gigahertz). 

Because the external clock determines how fast the CPU can communicate with the system memory it has a significant effect on the speed of the CPU in the real world.


Clocks and Instructions

The difference between the internal and external clock speeds of the processor is one limitation on its performance. Another is the number of clock ticks required to perform an instruction. 


While some instructions can be completed by marking one clock it can for example take four ticks to complete a multiplication operation. 

This will make a computer processor (CPU) that can for example add 4 GHz to one that reproduces at an effective speed of 1 GHz (gigahertz).


Putting It All Together

The three factors identified here work together to determine how fast a given processor will work. Sixty-four bits work on dual data at once like 32-bit chips giving them a significant boost in performance. 


Processors with faster external clocks can also exchange data with the computer faster than those with slower external clocks. 


Finally, processors with more efficient instruction sets that can work more in fewer clock cycles run faster than those that need more cycles to complete an instruction. 

Once you have marketed all of these factors, compare the processors of the computer to see what is faster by looking at the GHz (gigahertz) rating of the internal clock speed.