Overclocking is when you take a anything from RAM, CPU, GPU and up it. For example
When someone says they overclocked their CPU , they upped the voltage (Most of the time unless a slight change in clock)
After the voltage has been.....Upped they take the Core clock and up it to either the highest stable they can or OC it to what they need
Forexample, we will use a GTX 570 as an example
Use a free copy of MSI Aftr burner or EVGA Precision or ASUS's new GPU tweak tool. any of those works.
You simple up the voltage so the card has more power to run a higher clock speed. With a GPU you can change the Voltage, Core Clock, Shader clock, memory clock and even up the fan speed.
Ram is about the same concept between the two..
Ram you up the voltage as you would with both, but you instead of shader clocks and everything else. You simply raise the MEM frequency, and sometimes an option is available to modify the cas latency.
Do not attempt to OC your mobo's chipset, Tho i am sure it is hardly possible. Let the professional companys do the reasearching into that.
Also use proper cooling when Over Clocking. for CPU there is a million coolers you can choose from, from water kit's to your simple Cooler master Hyper 212 evo. Thus different coolers for the different level over clockers. If your gonna oc ram, i recommend a RAM heatsink on it or a RAM cooler that also monitors temps. as for GPU. its pretty much the same, some use EKM water blocks and some just use stock cooler..
I hope this has helped. Just reply here or a Private message and i will be glad to further answer questions
Please do not go randomly upping your voltages without researching and understanding the effect it will have on your components first
but to answer your question I believe Crush3d has it covered,
*Overclocking is the process of making a computer or component operate faster than specified by the manufacturer by modifying system parameters*
any other questions ask BEFORE altering any settings
Overclocking pertains to causing a processor, graphics card or RAM to run faster than it did out of the box. Years ago, when overclocking was new it was far more popular and significant than today. Today, these components are so fast and sophisticated that only the most complex 3D games will benefit from overclocking. Even the games benefit little compared to the time, money and risk put into overclocking. IMHO, it's mostly done for bragging rights as tangible results are minimal.
Overclocking also is one way of future proofing your system 3-5 years, Why? because the highset CPU stock speed right now is only 3.9 GHZ example i7 2700K 3.5 - 3.9 GHZ Turbo Boost. Overclocking depends on many factors like: CPU, MOBO, Vcore, chipset, CPU Cooler(air/liquid), PC CASE, Case ventillations, number of system fans installed on the case, the volume of air coming in and out of the PC case. The number one enemy of a CPU is high temperature. There are some overclocking guides in this forum for you to read and follow depending on what type of CPU and MOBO you have.