Under volting a laptop is a process where we limit the power to the processor in order to get higher clock speeds for a long period of time. This process is super risk free and can be done by anybody and we highly recommend to under volt your laptop to get the best out of it.
Usually the CPUs are given a bit more voltage than they actually need to run so that they can hit there extreme high clock speeds for just some second which helps the company to market the high clock speeds but the issue here is that the higher voltage will raise the temperature very rapidly which will immediately make the laptop to thermal throttle (thermal throttle is when the laptop reduces the CPU frequency to control the temperature), this will subsequently drop the clock speed to very low which decreases the performance by a great deal.
What undervolting does is it limits the voltage given to the CPU which helps the CPU maintain higher clock speeds for a long period of time as the CPU doesn’t get hot too quickly. This will improve the thermals, the fans will come on less which will make your device quieter, increase battery and improve performance by a great deal especially this will shorten the render times by a huge margin.