His numbers are way off. First a gaming computer is not "three refrigerators." A fridge/freezer combo uses like 400-800 watts when spun up depending on size and if it is frostless or not. Your typical reasonably high end gaming computer (high end quad core processor, single high end GPU) uses in the 300-400 watt range when fully spun up. There are, of course, higher end systems but they are not common as they cost a lot, for not a ton of gain.
Well the idea that there are tons of components or settings that'll just tank energy use is stupid. In terms of settings, ya those are default. By default a system will put its processor and GPU in to an idle state when not heavily loaded, and indeed most systems draw 90 watts or less when idle. In terms of componentry, there really isn't a ton of room for gain.
Like with PSUs. Any reasonable quality PSU that you might see in a gamer build is at least 80% efficient, and usually more like 85%. Go all the way to the high end, which many gamers already do, and you are only pushing 90-92% max. A gain, sure, but not much. If a system draws 300 watts DC going from an 85% (bronze) PSU to a 92% (platinum) PSU is the difference between 350 and 326 watts at the wall.
Then there's things like GPUs and CPUs. Well guess what? A give one is as efficient as it can be at a given performance level. There aren't the better and worse ones. You can't buy the efficient model GTX 980 and the inefficient model. They are the same. You can swap one kind of component for another and maybe gain efficiency. Like you can swap an AMD 390X for an nVidia GTX 980Ti and that'll use less power, but what if you want the AMD card?
Also there's the issue that usually the new ones are more efficient than older ones. Fair enough but in addition to the cost of upgrading that ignores the energy cost of producing the cards. Suggesting that everyone buy the newest shit all the time is not realistic, or energy efficient (a lot of our energy use goes in to making things).
This guy just doesn't know anything about computers. He's convinced that there's these vast optimizations that could happen, if only people wanted it. Not really the case.