Overclocking?

[AncientBoi]

Just as it says, What is "Overclocking"? Is it a good thing or bad?

 

[BigOnYa]

It's when you take a wall clock down and set the time ahead 15-20 minutes.....it's a good thing because you're never late anywhere again.

 

[FAST6191]

Chips of any real complexity don't magically do actions as soon as inputs are presented. They instead do them to the beat of a crystal, a clock if you will.
Not all chips can run at the same speed, however to make life easier then chip makers instead "bin" their devices according to ones that tests show they can handle (sometimes even putting them in lower ones if they lower grade batch is likely to be more popular and selling something is better than nothing).
Game consoles are an even firmer example of this as the big draw for many of them is a fixed piece of hardware (though lines get a bit blurry, especially on the original xbox) that devs can code to rather than a PC which could be anything.

Anyway as chips don't necessarily get used at their maximum (stable) potential people took to increasing the clock speeds. More beats, more actions done and thus more processing power. Also more power needed and heat generated.
This also brings on a secondary characteristic of whether frame rate is tied to a clock or is independent of it. Tied to is simpler and done more often in simpler devices and older games (though frame rate is a subtly different concept that has other considerations for this sort of thing), decoupled is more commonly seen in PC a like hardware wherein more CPU cycles means you either get more actions done and thus less chance of dropping down to a framerate you don't like (if the calculations don't get done in time there is nothing new to display) or more resources to put into better graphics. In the simpler thing though then increased clock speed might well result in the game being sped up. It also tends to mean everything else in the system might be running faster and that is not necessarily a good thing for certain aspects of hardware. PCs split clock signals up many times many years ago and thus you can more independently control things but I will leave that for another day, though I will say in more recent years then the only way to overclock is to pay for it by buying the fancy gear/models that allow it where things even as recently as 10 years ago were still pretty free (and these days I don't even bother looking at PC overclocking -- seldom produces anything of great merit compared to days of old where you could well "save" a lot of money or gain some very real results).

Good or bad. Your device, your rules. It is a way to sometimes get more from hardware than might have been officially available and more might result in a better experience for something. Heat (which speaks to hardware longevity), power, and stability may or may not suffer though.