2.0 GHz, 3.0 GHz processor speed. How often do we come across these terms and yet we don’t really know what it means? Let us find out.
Cycles in Processor
When an instruction is to be executed the Processor sends the address of the location from which data is to be fetched or written on the address bus and the command(reading or writing) on the control bus to the main memory and feedback is send back to the processor, this whole process can be called as one complete cycle.
Clock speed is the rate at which a processor executes a task and is measured in Hertz, Megahertz or Gigahertz (GHz). One cycle per second is called as “Hertz”. One million cycle/pulses per second is called as “Megahertz”. The greater the Hertz, the faster is your processor. However, the processor’s speed rating is just one of many factors that impact how fast it actually processes data.
Gigahertz (GHz) means 1 billion cycles per second and when you talk about 2.4 GHz processor, you usually mean that this is the maximum frequency of the clock to each core which is 2.4 billion cycles per second.
A single processor can have multiple cores that theoretically can have different clocks. Intel Dual and Quad core processor have the same clock speed to each core which is most common.
Any process like addition or multiplication has an instruction set which consists of instructions that need to be executed for that process to be considered complete. This instruction set is processed by the CPU at a certain speed usually called as cycles required per instruction.
A “simple” instruction set may require just 2 cycles of a processor. Processors may include “complex” instructions in their instruction set. A single “complex” instruction does something that may take up many cycles of the processor. Instruction sets can also be made “efficient” to execute them faster.
Some Processor Speed determining factors:
We have explained the basic idea, and not make it complex.
• Number of cores: A single core processor can execute just one instruction set. But a dual core processor can execute two instruction set. Similarly, a Quad core processor can do four instruction set simultaneously. The parallel execution is done by implementing some algorithms to prevent complications.
• Cache: Another important part is the cache which loads instructions from the RAM and feeds it to the CPU registers on request. If the data is not available, the CPU speed is slowed. Cache stores the most frequently used instructions so that the processor doesn’t have to fetch it from main memory again and again.
• Processor Architecture: A 32-bit processor can process a 32-bit instruction at a single time. A 64-bit processor can do operations on 64-bit instruction sets, increasing the efficiency and the speed. So, for adding two 128-bit number, the 32-bit processor may take up to 4 cycles (32+32+32+32 = 128) whereas, 64-bit processor can do it in 2 cycles (64 +64 = 128).
To know more about 32-bit and 64-bit processors read: 32-bit Vs 64-bit processor
Will two different processor run at same clock speed perform the same?
No, as we have discussed above the overall efficiency of the processor executing instructions is also dependent on the other hardware components that connect to the CPU, like the system bus, which transfers the data may be slower than the CPU limiting its ability to perform highest.
The number of cores may be different in both the processor, giving the advantage to one and disadvantage to another.
For example, An Intel Core i5 @3.46 GHz is not faster than an Intel Core i7 @3.0 GHz.
With technology like Intel’s Turbo Boost and Hyperthreading evolving with new generations of CPU, it is impossible to compare the performance of old CPU with the new CPU only on the basis of its clock speed.
So, the next time you are looking to buy a new device does not decide its speed based on only its processor’s clock speed. Look for the technology used.