###### Asked in Microprocessors

# CPU speed is determined by what?

## Answer

###### Wiki User

###### 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!