how common is overclocking? how much of a performance boost does it give? is there any risk with overclocking?
the performance boost isn't huge, but you might as well get the most out of what you paid for
when microchips are manufactured, there's what they call the "silicon lottery". basically all chips are not created equal, and some will clock higher than others. you at least know that the factory overclocked cards will be stable at whatever overclock they're advertising (and if it's not, you should return that shyt). and again, the assumption is that they will overclock higher than the reference/base cards
it's not really dangerous. if you push it too far, you'll get a driver crash, and you can dial it back and try again. this can be a tedious process of adjusting voltage and clock speeds to find the limit of your card
for the most part there's failsafes to prevent any serious damage. there will be additional wear & tear on the card, but that's where a good warranty comes into play. chances are in 3 years you'll want a new card anyway