A silly power question

[DiscoDave]

Apologies, this probably seems like a silly question but as I'm not 100% sure, I thought i'd ask.

I'm building a new homelab based on a ultra low voltage Xeon processor (25w TPD!) - it'll be on 24/7.

The lowest wattage PSU's I can find are circa 300W.

If my server is say, consuming 30W's of juice, from the 300W PSU, does the PSU only draw 30W from the wall, or does it draw 300W regardless of how power hungry the components are?

Cheers,

David

 

[AtaRo]

Your server will be pulling 30w of power from the PSUs output.

The PSU will always pull a little bit higher than 30w from the wall depending on the efficiency of the PSU at that load but not 300w.

Lets say the psu has 80% efficiency at 10% load, the power draw from the wall will be about 37.5w (30/0.8).

 

[DiscoDave]

Thanks, AtaRo