Overclocking is the process of forcing a computer component to run at a higher clock rate than it was designed for or was designated by the manufacturer.

Overclocking is usually practiced by PC enthusiasts in order to increase the performance of their computers. Some hardware enthusiasts purchase low-end computer
components which they then overclock to higher speeds, while others overclock
high-end components to attain levels of performance beyond what they were designed for.

Users who choose to overclock their components usually focus their efforts on
processors, video cards, motherboard chipsets, and Random Access Memory (RAM).

------------------------------------------------------------------------------------------------
Advantages
-The user can, in many cases, purchase a slower, cheaper component and overclock
it to the speed of a more expensive component.

-Faster performance in games, applications, and system tasks at no additional expense

-Some systems have "bottlenecks", where small overclocking of a component can help
realize the full potential of another component to a greater percentage than the
limiting hardware is overclocked. For instance, many motherboards with AMD Athlon
64 processors limit the speed of four units of RAM to 333 MHz. However, the memory
speed is computed by dividing the processor speed (which is a base number times a
CPU multiplier, for instance 1.8 GHz is most likely 9x200 MHz) by a fixed integer
such that, at stock speeds, the RAM would run at a clock rate near 333 MHz. Manipulating
elements of how the processor speed is set (usually lowering the multiplier),
one can often overclock the processor a small amount, around 100-200 MHz (less than 10%),
and gain a RAM clock rate of 400 MHz (20% increase), realizing the full potential of the
RAM

Disadvantages
-------------------------------------------------------------------------------------------------
The lifespan of a processor is negatively affected by higher operation frequencies,
increased voltages and heat. However, overclockers argue that with the rapid obsolescence
of processors coupled with the long life of solid state microprocessors (10 years or more),
the overclocked component will likely be replaced before its eventual failure. Also,
since many overclockers are enthusiasts, they often upgrade components more often than
the general population, offering further mitigation of this disadvantage.

Overclocking has a risky potential to end in component failure ("heat death").
Most warranties do not cover defunct units that result from overclocking activities


---------------------------------------------------------------------------------------------

Nowadays overclocking is made easier for pc users...
For instance the ASUS ROG RAMPAGE EXTREME which has Tweakit "joystick" whereby users get to use it to to optimize the performance outside of BIOS or OS.

ASUS ROG RAMPAGE EXTREME