Hardware

Hi there,
I have purchased a brand new Intel Atom board for my monowall and I was disappointed by it's power consumption: 30W
It is a no-name bulk power supply. I then tested with an "80+ Gold" PS which I use in my server: consumption dropped down to 18W

18W is still not great, but perhaps the best this MoBo can do, however I'm wondering:
there are these external PS which come with some cases, they are rated around 80-90W, while the full size ATX PSs (like those above) are rated no lower than 250W.
Does anybody here know, if those external PSs should be more efficient, even if they're much cheaper, but simply because they're not so overpowered?

Thx,
reach

Yes, no and maybe.

The deal is that power supplies are most efficient at 80% utilization.  So a 400 watt power supply is best at 320 watts.  But some of the better MiniITX motherboards can run on a little as 7 watts.  So, yes, even a cheap 1Amp wall wart can give better efficiency that an 80Plus 150 watt power supply.

What you need to find out is what your motherboard actually needs with your RAM and and the flash drive.  You might be OK with a 24 watt (2amp) based on your numbers so far.

Update:
I have now tested with 2 different Gold+ PSs, once rather cheap one and one fanless from Seasonic, both need 18W.
Now I've got a cheap chassis + external 40W PS (47EUR, made in China) and this needs 17W.
So it appears that these low specced power PS are indeed more efficient in the low power area, even if they're very cheap.

That is still only about 40% load.  Try a 2 amp PS, and I bet you get down to 15 watts.

Try a 2 amp PS, and I bet you get down to 15 watts.

what is that and where do I get it?
BTW: it's a 60W PS, not 40. "even worse" :-)

First, what Atom board?  Some have 12v barrel connectors.  But if not and you need ATX, this is the most efficient low power I know.  http://www.mini-box.com/picoPSU-90-XLP

I would also have a look at pico PSUs.
And thus, I would have a look at that review : http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=207