draw on eATX 1100W PSU

[Sho'Nuff]

Question: Does a PSU draw the total rated wattage from an outlet at all times, or only when the components it is driving require the extra juice? I am upgrading to a 1100W PSU and am trying to determine whether I need to buy a new battery backup system as well (my current one is only rated to 750W.

 

[mpilchfamily]

The PSU only draws what the system needs. But you also have to consider efficiency. Due to the way AC is converted to DC there is always power lost in the form of heat in a PSU. The better the efficiency the less power is lost.

Lets look at a typical system power draw. The average system will only pull on average about 200W from the PSU. Now lets say you have a 500W PSU tat is 80% efficient. Well then that 200W draw by the system would be about 250W from the wall. If that PSU is only 75% efficient then you will be pulling about 267W from the wall.

Now there are many other factors involved. Such as most PSU are at there most efficient while under a mid range load. Also as temperatures rise the efficiency goes down. So because of all of this the efficiency rating is an average and not the actual efficiency you may encounter.

So in the end you will be fine with your current UPS. But if your system power needs aren't close to exceeding 600W to 700W then why get a 1100W unit?

 

[Sho'Nuff]

Couple reasons I upgraded:

1. My old PSU was on the fritz (computer was randomly rebooting, new PSU fixed this)

2. investment for the future. Newegg had a good sale, and I am probably going to go SLI eventually.

 

[mpilchfamily]

Cool.

But there is nothing about a computer that i would call an investment. Once you buy in aitem you won't be able to sell it for the same price or higher then what you paid for it.