Most efficient ATX power supply for 50-100W loads?

kike_1974 · Post by **kike_1974** » Fri Apr 11, 2008 1:22 pm

I'm looking a standard ATX PSU for a 24/7 server which consumes only about 40W DC at idle and 80W DC at load. I need it to be as much quiet as possible.

I do not consider solutions as picoPSU and such, I prefer a standard ATX.

Which PSU is the most efficient at these low loads?

ntavlas · Post by **ntavlas** » Fri Apr 11, 2008 5:21 pm

The recent spcr review of the 250W sparkle has some useful comparisons but I think you can do better.

Those three should be the most efficient in the power range you`re after:
Akasa Power80+ 400 (82+ capable)
Enermax PRO82+ 385
FSP Zen 400

The Enermax is a smaller model of the one reviewed here.

andyb · Post by **andyb** » Fri Apr 11, 2008 5:27 pm

The new Enermax range (the lowest poer should be good).

Why dont you want to consider the PICO PSU as an option.??? This is more ideal for your power range usage than anthing else on the market, and it doesnt need cooling (inside your PC).

Andy

kike_1974 · Post by **kike_1974** » Sat Apr 12, 2008 7:26 am

Because of reliability, I think I would be in the limits of the picoPSU and I don't think it is a good idea, but maybe I'm wrong. I also think it is an expensive solution.

My system uses a ga-p35-ds3, an E2160 undervolted (1,[email protected]) and an ati HD3650. Only 1 HD (about 10W max peak).

I've been looking at the enermax modu82+ spcr review and it looks like it reaches almost 80% efficency at 50W DC which is impressive. Maybe the 385W pro82+ or the 425W modu82+ can reach even better figures. I like this option for now, does anyone have efficiency figures for these PSUs at 50W loads? I most reviews they start measuring at 100W or so... it looks line noone is interested in these low loads except spcr

EDIT: Looking at this review it looks like the 625W behaves better than the 385W and 525W at low loads at 230VAC input, and it is more silent too. It is hard to believe

Bluefront · Post by **Bluefront** » Sat Apr 12, 2008 7:48 am

For that sort of draw, a 120W PICO is ideal. I don't know what you'd have to pay to get one, but it would be worth it. They don't make any noise, they run cool, and they don't take up any space. How can you beat that?

kike_1974 · Post by **kike_1974** » Sat Apr 12, 2008 8:00 am

I've been looking at the specifications of the picoPSU and it supports a max load of 7A in the 12V line, that is 84W. The max peak is 10A (120W) but only for a maximun time of 10s.

I still think that I'm near the limits of this PSU for my system... am I wrong?

yuu · Post by **yuu** » Sun Apr 13, 2008 4:11 pm

so i guess pro 82+ 385 draws 2W more

1-2% less efficient after all

mine is 2140, 2*1Gb pqi, 8800GT, cheap fortron PSU
1.6Ghz @ 0.8875 109W in occt
1.86Ghz @ 0.975 114W in occt
same with 1*1Gb module back to 109W
idle 92-96W

so ~ 85W DC max but think 8800 - 3850 ~ less 20W, and 1 module less 5W when 266fsb used, when 400fsb is used - 1 module is somehow 10W less

Bluefront · Post by **Bluefront** » Mon Apr 14, 2008 12:46 am

You can also get a version of the PICO that is 200w. It sometimes needs a extender cable for the MB plug. I think this outfit also sells an 8.5A power supply for it. I have one system running with this for two years or so, using 180w power supply from Radio Shack.

bexx · Post by **bexx** » Mon Apr 14, 2008 6:24 pm

I don't really understand how the 120watt pico gets its' rating. Isn't the 12v just passed through from the brick? What is limiting the 12v rail to 7 amps or whatever with the pico PSU?

The problem I have with the 200watt version is on my board the power connector is right next to the dimm slots... I can't find any extenders execpt for the 8" cable ones... I just need like 1 or 2 inches. Any way to resolve this or is it a lost hope?

BTW this is the board:
http://www.phoronix.net/image.php?id=66 ... 5_mobo_lrg

I might get the 120watt Pico just to see what happens... mobo+1.8ghz c2duo + 2 dimms, onboard gfx and sound... gotta be low enough for pico.

bexx · Post by **bexx** » Mon Apr 14, 2008 6:49 pm

Manual for the 120watt pico actually has no info for the 12v output, it just says 'switched', no regulation info... what the heck does it do? Anyone ever push it past 10amps or whatever the limit is supposed to be?

If you search this on ebay, 220watt brick for $30...
Dell DA-2 Power Adapter M8811 D3860 MK394 220W 12V 18A

Ima order for the hell of it, with fingers crossed.

mcoleg · Post by **mcoleg** » Mon Apr 14, 2008 11:53 pm

how do plug D3860 into pico though?

bexx · Post by **bexx** » Tue Apr 15, 2008 12:32 am

Yea one of the connectors needs to be changed but not the end of the world.

http://smallandquiet.blogspot.com/2006/ ... power.html

He ran into similar problem. This is still a for-fun project... no big deal if I run into problems

.

mcoleg · Post by **mcoleg** » Tue Apr 15, 2008 4:59 am

i see; i sux with soldering...

Maverickâ„¢ · Post by **Maverickâ„¢** » Thu Apr 17, 2008 2:48 am

I'm thinking to get the Akasa Power80+ 400, the test's results in 80plus site are very impressive, but in this Matbe review (http://www.matbe.com/articles/lire/342/ ... age135.php) I don't understand the reason of the big difference between this PSU and the Fortron Zen 400.

What do you think?

EDIT: I've seen only now, maybe the difference is due to the fact that Akasa is a 500 watt PSU?

Michael Sandstrom · Post by **Michael Sandstrom** » Fri Apr 18, 2008 11:35 pm

Although I have not seen a review, the 425w Modu82+ that I recently moved to is much more efficient than my old Seasonic SS-400 at idle. Measured with a Seasonic Power Angel the SS-400 used 71w at idle vs 64w for the Modu82+. I hope SPCR tests the 425w Modu82+ soon. I think the unit will have great appeal even at low outputs. My Modu82+ fan spins quietly at 463 rpm.

kike_1974 · Post by **kike_1974** » Mon Apr 21, 2008 9:03 am

"quietly at 463 rpm"... does it mean without any kind of clicking or ruttling noise?

If it is so, I'm definitely getting this PSU

. I'll just wait for the SPCR review for confirmation.

Ant6n · Post by **Ant6n** » Mon Apr 21, 2008 7:31 pm

btw, for the pico/pwm200 one can get the dell optiplex adapters, they have 150 and 220 Watt versions, usually on ebay for 25-40$ shipped. The plugs are different size, so you have to solder a different ones to the adapter (I have not found sockets for the 150W brick, although the 220W seems to be some sort of molex).
Alternatively, i've seen a lot of 'lcd ac adapters' popping up on ebay lately; they are rated for 12V@120W, appear to have the right plug, and go for 30$ shipped (I just got one to test it and put together with a pico; i'tll be a while before it gets here from Hong Kong, though).
I believe none of these ac adapters has a fan, for sure the 150W optiplex one doesn't.

Michael Sandstrom · Post by **Michael Sandstrom** » Mon Apr 21, 2008 10:55 pm

kike_1974 wrote:"quietly at 463 rpm"... does it mean without any kind of clicking or ruttling noise?

If it is so, I'm definitely getting this PSU . I'll just wait for the SPCR review for confirmation.

I do not hear any clicking or other noises from the Modu82+. The only computer noise that I can identify is a 120mm Nexus case fan running at 630 rpm fed by Fanmate minimum voltage. I have seen others who have reported minimum Modu82+ fan speeds of 479, 480, 500 and 503 rpm. The 500 minimum rpm was reported by Mike Chin in his 625w Modu82+ review.