Hello, I am LostElement, but you can just refer to me as LE. I will be adding a lot of imformative stuff for you guys so you can better make a decision on building your PC. It's not done (Yet!) but I intend on working on it and updating it!
Why is choosing a good power supply important?
Well, quite simply, the power supply is the most important component in your rig because it's the only component in your system that can damage your hardware even if the PSU is "working". A good performing PSU will ensure that your hardware will receive clean power and won't get damaged because of poor performance.
For example, if you have the EVGA SuperNOVA NEX, don't fret. It's not a horrible PSU, but it's not a great one. It won't blow up on you, but there are better options. You don't need to replace that PSU. But there's no reason to buy a NEX today. Same goes for other PSUs like Corsair's builder and CSM series.
"What do I look for when choosing a power supply?"
If you don't want to try to learn the complexities of a power supply and electrical engineering, then you can simply resort to professional reviews. What classifies as a professional review? Someone that had load testers and other testing equipment and tests the power supply's performance, someone that can take a part a power supply and identify every component inside, and has extensive knowledge in electrical engineering. Quite simply, these two sites are good for those kinds of reviews. JonnyGuru.com and TomsHardware.
Consumer or YouTuber reviews literally do not matter. All they can say is that the system turns on.
Another thing to note that efficiency does not speak to the quality or performance of a unit. For all you know, the unit cannot output its rated wattage or its rated efficiency.
Power Supply Terms that you'll see me use:
List of some of the best PSUs available:
List of good PSUs:
List of meh/okay PSUs:
PSUs to Avoid:
What might happen if you cheap out on a PSU: https://m.youtube.com/watch?v=jrWDKYNu72Q
This is a worst case scenario. Most modern PSUs may just pop and die.
What is Bottlenecking?
A bottleneck is a phenomenon where the performance or capacity of an entire system is limited by a single or limited number of components or resources. The term bottleneck is taken from the 'assets are water' metaphor. As water is poured out of a bottle, the rate of outflow is limited by the width of the conduit of exit - that is, bottleneck. By increasing the width of the bottleneck one can increase the rate at which the water flows out. Such limiting components of a system are sometimes referred to as bottleneck points. - Wikipedia
Everyone is affected by bottleneck one way or the other. The question is: How much is it affecting you? Well, it completely depends. What's your resolution, your graphical settings, what game you're playing, how much load is on the component(s), etc etc. It's not a yes or no thing.