Ok, so I have a GTX 1080 ti and it uses 600 watts of power, but I only have a 550 watt power supply. It is going to be a while before I get a new psu, so I want to know how I can underclock my gpu to only use 550 watts. I heard my gpu or psu or possibly other parts could get damaged from not having enough power.
Your 1080ti will not use 600W. You require a 600W PSU to power your entire system. Your GPU may account for half that at full load. You don't need to underclock it just don't run games at maximum settings. More fps requires more power requirements. I don't think it's possible to damage electronics by not supplying enough power, they just simply wont run.