Power supply unit and UPS

[jerry22]

hi guys,can you take a look at this please

 

i will buy a power supply of 550W. my computer will need to use 436W (ive used a watt calculator).
so, will the psu draw 436W or 550W of power from the wall?
i would like to know because i'm buying an UPS. will a UPS of 550W be good enough to keep my computer + monitor (45W) on for like 4-5 minutes, just the right amount of time to save and shut it down?
also, i've read that PSU will draw 130W more from the wall only for delivering power. is that true? so for istance: a 550W PSU will actually draw from the power 550W plus a certain percentage, depending on the quality of the psu, so maybe 675W total?

i need to know all of that because i want to buy an UPS and i need to know if a 550W UPS is good enough(computer + monitor) or if i need a higher capacity

 

thanks
regards

[Godlygamer23]

2 minutes ago, jerry22 said:

i will buy a power supply of 550W. my computer will need to use 436W (ive used a watt calculator).
so, will the psu draw 436W or 550W of power from the wall.

It depends on the load from the system. The power supply will only draw what's required, but even with the power supply under full load, it will not draw 550W due to efficiency(it's not 100% efficient. Some power will get lost as heat, hence the higher power draw). The power supply will not draw the maximum that's required, nor will it draw what it can personally take. It will draw what the system is required, and if the system goes beyond its capabilities, it should shut off.