PSU actual power draw?

[Stonejaw]

I was wondering about actual power drawn from the wall from PSU's. For example if I have a 600W power supply will that draw the full 5A from my 120V wall socket at all times no matter how many hard drives/optical drives I have installed in my box or will it only draw the amount needed. I ask this because Im not sure exactly what happens when the AC is converted to DC.

So then if I had a 1000W PSU and only really needed 350W then thats all it draws correct? I just want to save money on power usage so I dont want to waste electricity.


Thanks

 

[Dangman]

So then if I had a 1000W PSU and only really needed 350W then thats all it draws correct? I just want to save money on power usage so I dont want to waste electricity.

That is correct. I have a 520W PSU but my rig only draws 182W at load. And thats all the PSU will draw.

 

[NKDietrich]

I was wondering about actual power drawn from the wall from PSU's. For example if I have a 600W power supply will that draw the full 5A from my 120V wall socket at all times no matter how many hard drives/optical drives I have installed in my box or will it only draw the amount needed. I ask this because Im not sure exactly what happens when the AC is converted to DC.

So then if I had a 1000W PSU and only really needed 350W then thats all it draws correct? I just want to save money on power usage so I dont want to waste electricity.


Thanks

Yep. Well, a little more than 350W, since its not perfectly efficient, and generally is between 75-90% of what you're pulling from the wall.

PSU wattage is a capacity rating. A lot of subpar 600w PSUs for instance will blow up once you load them to 350-400, and another brand may sell a similar quality PSU but correctly label it a 300w.