PSU question

[MarcoPolo]

i am currently using an i7 4790 + itx board + 16GB Ram + SSD.
Not using any graphic card and have no plans to install any.
Using an ATX case with cooler master 550M PSU.
I suspect the system require less power than 550W.

So does the PSU eats up 550W from my utilities bill even when the system does not require so much? so does the PSU scale up/down according to what the system requires?

i was thinking of getting a In-Win Chopin with a 150W PSU, or BQ series.
According to the In Win website, the BQ series does not support CPU above 65W and below. Does this means i should not be getting the Chopin as well?

 

[wwenze]

Your system is like a tap and your PSU is like the pipe... your tap controls how much water flows out, the pipe just needs to be big enough.

i7-4790 TDP is 84W, after adding other components you are close to 150W. Plus all the heat needs to get out of the case. Possible but not advised.

 

[Firefly01]

So does the PSU eats up 550W from my utilities bill even when the system does not require so much? so does the PSU scale up/down according to what the system requires?

The PSU's power rating refers to the maximum power it can provide. Its power draw from the AC mains is proportional to the power it is actually sending to your components.

However, because the PSU is converting AC current to DC, there are losses, mainly through heat. Therefore, if you are concerned about your energy usage, you should be looking into getting an energy efficient PSU.The 80 plus standard is commonly used when talking about PSU efficiencies. Furthermore, you should always leave some headroom when calculating the PSU rating that you need. Operating a PSU near or at it's maximum rated output is generally not as energy efficient, plus if you decide to add something to your build, you will most likely not have enough power for the new component.

Also, you may want to look at your components. A motherboard with lots of bells and whistles will draw more power (extra input power phases, additional on-board controllers, etc) than a simple one. Running two sticks of RAM will draw more power than just one.