The power supply is one essential part of a computer that often is being overlooked. The wattage of your PSU should always be bigger from the power draw from all the components inside of your PC. There is a web calculator that can help you to understand how powerful PSU you need to buy.
https://outervision.com/power-supply-calculator
You literally need to select all the parts in your PC from the drop-down menus and the blue "Calculate" button and you will get a result like that:
If for some reason you cannot or don't want to use the web calculator you can do something else. Google your video card's TDP(Thermal design power) - that is the maximum amount of electricity your card is supposed to use. Depending on how many video cards you will be using on this machine add all their TDPs. For example, if you have Nvidia RTX 3060TI and RTX 3080 you have to summarize:
200W (3060TI) + 320W (3080) = 520W
Once you have this number - 520W, you should also add 100W on top of that. Those are for the rest of the components in your PC - like CPU, RAM, HDD/SDD, fans, RGB.
520W+100W=620W
On top of that, I would advise adding another 25%.
620W x 1.25=775W
The last 25% are there because of the fact that the PSU is never 100% effective. There are several tears of PSU ratings that you can see in the table below:
Load 80 Plus Bronze Silver Gold Platinum Titanium Efficiency 20.00% 80.00% 82.00% 85.00% 87.00% 90.00% 90.00% 50.00% 80.00% 85.00% 88.00% 90.00% 92.00% 92.00% 100.00% 80.00% 82.00% 85.00% 87.00% 89.00% 94.00%
It is important for you to understand what those raising mean. If you have 1000W Gold PSU it draws from the wall 1000Wats, but it delivers to the system only 87% of that (870Wats) under 100% load and 90%(900Wats) under 50% load.
Another thing to consider is the number of 6+2 pin connectors your PSU has. This will matter if you are using multiple video cards that need 6 or 8 pins of additional power(higher-end video cards always require 1 or 2 additional 6 or 6+2 pin connectors). It is not recommended for you to use Molex or SATA to PCI-e adapters, especially if you are going to be mining.
TOP PSU Manufacturers list you can find here.
Consider the fact that in the future you might want to add more hardware to your PC and if your existing PSU will handle it.
I hope this was useful guys.
