Dont get overkill with psu. I ever watch guy running i7-8700k and 1080 Ti with 450w cooler master psu. It works fine
Please refrain from those comments. We are a community that know better than suggesting pairing a Cooler Master 450w PSU with a 1080 Ti and a i7-8700k. Cooler Master is one of the worst you can get and a 1080 Ti with a 8700k will not work with a 450W unless it's platinum quality and even then, you would push it.
PSU is the heart of the system. You should never go cheap on it, unless you want to risk each and every component of your system when it fails and takes something with it.