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CPU speed is determined by what?


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December 15, 2009 11:22PM

There are several ways in which CPU speed can be measured. The most common unit is a hertz, such as 3 gigahertz. 1 hertz is another name for 1 CPS. A CPS is a Cycle Per Second. So 3 gigahertz would mean that the CPU is doing roughly 3 billion cycles per second. (A giga in computer speak means billion.)

This was the most common form of measurement during the Pentium Chip era. The last Pentium chips were reaching 3.8 gigahertz. However, you may notice that newer chips such as the Core series by Intel have much fewer hertz, but run much faster. That is because the CPU manufactures learned that there are better ways to make a CPU faster than just by increasing the hertz.

With newer CPUs they have put two or more processor cores on the same chip. These processor cores work in tandem. By working together and sharing the processing load, the overall speed of the computer is greatly improved despite the fact that they are running at slower hertz speeds.

Another way to measure the speed of a CPU is by using FLOPS (FLoating Operations Per Second). 1 FLOPS is generally considered 1 addition or multiplication operation in the processor, however FLOPS also pertain to exponential, sine and cosine. FLOPS do not have as much merit in home computing as they do in research super computers because research uses more mathematical types of computation.

It is hard to compare actual FLOPS between CPU architecture. A Graphics Card Processor (GPU) would consider an exponential 1 FLOPS while it would take many FLOPS on a normal CPU. GPUs can compare FLOPS much better than CPUs because they do use mathematical calculations for their graphics rendering.

Some basic FLOPS highpoint counts of Processors as of Jan 2010 are as follows:
Pentium 4 - 7 gigaflops
Core2 Quad - 70 gigaflops
Xbox 360 CPU - 115 gigaflops
Playstation 3 CPU [Cell Processor] - 218 gigaflops
Xbox 360 GPU - 240 gigaflops
Playstation 3 GPU - 1800 gigaflops (1.76 teraflops)
nVidia Geforce GTX 295 [top PC graphics card now] - 1788 gigaflops (1.75 teraflops)
Jaguar [top super computer now] - 1,759,000 gigaflops (1.75 petaflops)
Folding@Home Distributed Computer [as of now] - 8,500,000 gigaflops (8.10 petaflops)

8.10 petaflops is 9.11978925 x 1015 FLOPS or 9,119,789,250,000,000 mathematical operations per second!