[Nexus 10 General] EniGmA1987:
The three most damaging things to a processor are: amperage, voltage, and heat. Heat is tricky, because every processor has a maximum heat limit it is designed for. The more heat you have the less life your processor will have. However, if you stay within its maximum heat limitations then the processor will still last many many years, as soon as you get above that heat limit you start damaging the processor extensively, greatly lowering its lifetime and possibly causing irreparable damage in that you can no longer run at the higher core speeds stably anymore. So you always want to stay within heat limitations, preferably as cool as you can.

Amperage is also highly damaging to processor silicon, but thankfully we dont really control this up or down on most processors. One good example of this can be seen with RAM, which you can control amperage on. The best example here is RAS to RAS timings, which is when the RAM chips get pulsed with large amounts of amperage. It has been many many years since I looked into the technical details of this, but I *think* this happens when a row of addresses is pre-charged before access or something like that. Normally this happens every 4-6 cycles on average. Many people in order to increase stability of their RAM overclocks would lower this, I even did some stuff for a while with a setting of 1 for this timing. Because of low values on this timing the RAM is getting pulsed with large amounts of amperage quite frequently and this was causing massive degradation of the cell structure and creating micro-holes in the silicon. These holes then in turn require more amperage to remain stable at your MHz speed in order to overcome the damage, and with the higher amperage needed you continue to accelerate the damage. It is just a snowball effect of damage to the RAM chips that leads to complete death of the chip in a few months. This was why you saw large failure rates on DDR2 RAM at one point "back in the day" when D9GKX and GMH chips were all the rage. So all that to say, large amperage is bad for computer chips.

Next up is voltage, which we do control. More voltage is needed for high MHz speeds as we need to make the transistors switch faster and have more power to give in order to achieve higher speeds. Higher voltage leads to greatly increased heat output, greatly increased battery drain, and also if you are using voltage above the chip's specifications causes damage to the processor itself. Lowering voltage is the best thing we can do to keep our processors running at their best. A tiny decrease in voltage will often be 1-2 degrees cooler in temperature, and usually means a few less watts as well (depends on chip architecture). Just last week I was overclocking an Intel i7-3930K processor. I had fun playing around with it and observing the changes happening. I observed with 1.4v and 4.5GHz core speed than power draw was 198 watts under 100% load. Going to 4.6GHz raised power draw up to a nice even 200 watts (2 watts more for 100 MHz). I then went back down to 4.5GHz speed and increased the voltage from 1.4v to 1.42v, and saw a temperature increase of 4-5 degrees on all the cores and a 6-7 watt power consumption increase. Just from raising the voltage that little bit.

So the best thing we can do for our tablets is to undervolt. But when overclocking, as long as you stay within the chip's voltage limits and heat limits, the extra core speed doesnt really affect the chip's lifetime at all, until you get many MANY MHz ahead of its design. if you can overclock up an extra 300MHz while still dropping voltage a bit you will see both a reduction in power consumption (even with the extra speed) and a reduction in heat. Although these reductions will not be as much since we are also generating small bits more of power draw and heat from the higher speeds too.

TL;DR

overclocking is fine and wont damage your processor as long as you remain at the same or less voltage and heat output.