What exactly is overclocking?

Im sure most of u might have heard the term "overclock" at least once. I dont know much about overclocking. Read up a bit and thought i'll post here. Well for a pc to work correctly everythin in it is synchronised using a clock signal(the same square wave which we kept drawing for timing diags in mup). Every device inside the pc works in sync with a clock signal which a device may multiply and use according to its need. So technically the raw processing speed of the pc is based on the frequency of this clock signal. So IF we alter this signal we can get our pc to run faster. But like any good thing in this world there is a catch, in fact lots of them. Will come to them later.

Simply put, to overclock is to make your pc components run at a faster clock rate than they were supposed to run by the manufacturer.

There was a question that sprung up in my head after i came to know this much. If this is possible why cant the manufacturer simply make it run faster and sell it at the same price?? Think ive found the answer thanks to wiki. Its like this. Consider the processor. Manufacturers use the same assembly line/technique to manufacture processors of different clock speeds. The speed that appears on the label is the max speed at which that processor worked successfully under the worst operating conditions(highest temperature and lowest voltage). Hence the manufacture is sure that the processor will operate at the labelled speed over an entire range of temperatures.
So if we keep the operating conditions at a constant level(constant temperature) we CAN get them to run at higher speeds.

People overclock a variety of components like the CPU, RAM,graphics card etc.
One of the main motives is to buy a cheap component and overclock it to run at par with costlier components. Now the catch

When a component is overclocked it generates more heat that it used to generate. This calls for xtra cooling. Sometimes minor overclocks mayb possible with the existing cooling. But a considerable overclock calls for better cooling. People use more powerful fans, water cooling or even methods as far fetched as liquid nitrogen. The people at tom's hardware guide(the site thats there in the links section of this blog) actually used liquid nitrogen and overclocked a Pentium 4 3.4Ghz HT processor all the way upto 5Ghz which was faster than the fastest desktop processor under development at that time. I think the video is still available for download there.

Also when a component is overclocked its operating at conditions it wasnt designed for which can cause undesired functionality. An overclocked system maybe fast but may sometimes crash thrice every 10 mins. Sometimes the instability isnt visible but the data which gets written to the Hard disk and all keeps getting corrupted.

Also overclocking involving voltage increase can result in the component getting damaged beyond repair(plus in most cases ur violating warranty norms when u overclock). Another option is a factory overclocked component where the vendor tests the overclocking capability of a component and sells it overclocked for a slightly higher price with warranty.

I havent ever seen or done an overclock(though i have underclocked my pc). Underclockin is lowering ur clock speed and voltage settings to save power(especially wen ur pc is on all night for downloading). Underclockin is kinda harmless and i dont think it does any damage.

Another fact about overclocking is some vendors prevent overclocking by removing options for setting clock speeds and multiplier values manually(my motherboard dosent have any overclocking options). I dont think overclocking is something which each one of us should practice at home:D But its worth knowing. If youve read this far, do post a comment;)