Britec Tech Support Forum

Calculate How Many PSU Power Supply Watts Used: Some time you may want to know roughly how many watts you computer is going to use, with this online site, you can calculate how many watts is need, remember this is just a guide, but should help you buy the right size power supply, remember if it says 700w on the PSU and its not a branded power supply and cost £20 or $40 its not going to be a good PSU and not have many amps on the rail and power you may need.


eXtreme Power Supply Calculator Lite

https://powersupplycalculator.net/

I use this one it gives you a graph at end showing different components load.

Good info. Also in general the least amount of rails on a psu usually translates to higher amperage on each rail. Most decent psu's now have just 2 rails.