High-efficiency, low-power PSU (Delta or HiPro)

PSUs: The source of DC power for all components in the PC & often a big noise source.

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craigpardey
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Joined: Sun Feb 08, 2009 5:32 pm
Location: Toronto

High-efficiency, low-power PSU (Delta or HiPro)

Post by craigpardey » Thu Feb 12, 2009 4:34 am

I'm looking for a quiet, high-efficiency, low-power PSU for a box that I'm building which will probably idle around 50W.

I have looked at the list on 80plus, but most of the Gold-rated ones are in the 500+W range and suck in the 50W range.

I am considering either a Delta DPS-255EB A or a HiPro HP-D2551AO O1LF

A few questions:
* Can anyone find either of these for sale in North America?
* Any idea how quiet they'll be?
* Should I just stick with the tried-and-true Seasonic S12II 330W

jessekopelman
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Post by jessekopelman » Thu Feb 12, 2009 3:04 pm

Why go crazy trying to get 87% (Aka Gold) efficiency at very low loads? At 50W DC demand 80% efficiency gives you 62.5W AC draw, 82% gives you 61W, 85% gives you 59W, and 87% gives you 57.5W. That's only 5W difference. At lower demand the difference will be even less. Is it really worth extra money and effort to save 5W or less? 24/7 use at $0.20/kWhr values a 5W at $8.76/year. 300-400W 80+ units from reliable vendors are easy to come by at ~$50. For $10 or so more you can get Bronze rated ~400W units. Hard to say whether a 400W Bronze unit would be better than an 300W 80+ unit, for your application, given that 50W is closer to the 20% load that the efficiency is certified for on the 80+ unit, but the Bronze unit might well be better in any situation thanks to superior components.

Tobias
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Post by Tobias » Thu Feb 12, 2009 3:49 pm

jessekopelman wrote:Why go crazy trying to get 87% (Aka Gold) efficiency at very low loads? At 50W DC demand 80% efficiency gives you 62.5W AC draw, 82% gives you 61W, 85% gives you 59W, and 87% gives you 57.5W. That's only 5W difference. At lower demand the difference will be even less. Is it really worth extra money and effort to save 5W or less? 24/7 use at $0.20/kWhr values a 5W at $8.76/year.
It depends on how you look at it. My PSU is more than 5 years old now. When I bought it, it was top of the class in efficiency, now it's not even close. Back then the cost of electricity was way less than half of what is now as well and people were also quoting efficiency numbers and calculating powersavings etc.

Don't get me wrong, it is a valid argument, I'm just saying that things changes. There is no stable equilibrium in human life and one thing we have learnt the last years is that energy will become more expensive, not less. There are other, more long term reasons to buy highly efficient components as well. Comparing a gold certified PSU with my PSU it is clear that something has happened. It isn't driven by altruistic PSU manufactorers, though, but by the market demand. We have 80+Gold PSUs today because a lot of consumers demanded higher efficiencies in their PSUs.

However, if environment concerns are the reason to upgrade, then the high costs of energy to produce and ship a unit should be noted. There is no way a replacement unit will save enough electricity to make up compared to an old unit that still works, regardless of any difference in efficiency.

Back on topic. I think someone managed to work out that Dell uses at least one of those two PSUs in two of their optiplex series (can't remember which ones, "use the search, Luke"). If I know Dell right and you get hold of one of their salespeople, it might be able to order one as a sparepart. Then again it might be my Dell contact sucking up to me because he knows I'm the one ordering all the hardware for our company...

jessekopelman
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Post by jessekopelman » Thu Feb 12, 2009 4:04 pm

Tobias wrote: It depends on how you look at it. My PSU is more than 5 years old now. When I bought it, it was top of the class in efficiency, now it's not even close.
Yes and by this argument you should never go to extremes to get the top of the line, as there will always be something better out soon enough. Why spend $200 getting the best PSU now when you can spend $50 getting something very good and replace that in 5 years with something that is likely better than the $200 PSU of today?

Tobias
Posts: 530
Joined: Sun Aug 24, 2003 9:52 am

Post by Tobias » Thu Feb 12, 2009 11:57 pm

The question is what is most important? To buy the cheapest possible psu (and signalling that price is the most immportant) or buy the best possible psu (signaling efficiency is most important)? Buying a 50 buck psu will never change anything. Paying a premium, showing the manufactorers that there is a premium to be gained for hogh efficiency products on the other hand... :)

ex.treme
Posts: 64
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Location: Czech Republic

Post by ex.treme » Fri Feb 13, 2009 6:15 am

Hi!

I'M looking high efficiency psu over 3 months. The best in stock item i found is FortronFSP 250w. - 85% at 20 and 50 % load.
http://www.watt-power.co.uk/catalogue/w ... p-351.html

But i still searching better psu. Now i'm still searching on websites Dell Psu from Delta or Hipro with 85-88% efficiency from Optiplex 760,960. - 235 or 255w
Power supply 85 plus in Optiplex 360
http://www.dell.com/content/products/pr ... =bsd&cs=04

Power supply 88 plus in Optiplex 760 or 960
http://www.dell.com/content/products/pr ... =bsd&cs=04

I found also the best gold 80plus.org Dell psu RM112 with efficiency over 90% but price Starting From $179.991 ;-)
link: http://accessories.dell.com/sna/product ... &~lt=print

Now i'm searching used psu on ebay atc. from Hi pro Delta atc, and maybe i found Delta or Hipro 255w ... gold.

I wish you one thing: good luck

jessekopelman
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Post by jessekopelman » Fri Feb 13, 2009 10:10 pm

Tobias wrote:The question is what is most important? To buy the cheapest possible psu (and signalling that price is the most immportant) or buy the best possible psu (signaling efficiency is most important)? Buying a 50 buck psu will never change anything. Paying a premium, showing the manufactorers that there is a premium to be gained for hogh efficiency products on the other hand... :)
What about the third alternative: buying the best PSU for the money? If you are too eager to pay a premium for a high efficiency PSU the only message you are sending is that manufacturers should always charge a premium for them as the target customers are price insensitive. Doesn't it make more sense to oreint to products that are a particularly good value? Like buy that $50 80+ PSU instead of the $30 who-knows-efficiency PSU, but forget the $200 PSU. There is a happy medium here. Extremism is always bad . . .

justyn
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Joined: Wed Feb 25, 2009 5:15 am
Location: UK

Post by justyn » Wed Feb 25, 2009 5:22 am

That Dell RM112 looks amazing. According to it's "80 plus" testing report the efficiency keeps improving as load get lower, even at 20%.

Does anyone know any more about this PSU?

Has anyone seen anything else like this? Better than 90% efficiency when the system is idling at 51w seems streets ahead of anything else.

EDIT: typo
Last edited by justyn on Wed Feb 25, 2009 7:28 am, edited 1 time in total.

line
*Lifetime Patron*
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Location: Israel

Post by line » Wed Feb 25, 2009 6:32 am

justyn wrote:Has anyone seen anything else like this?
The Dell H255E-00 originally had a similar curve (see e.g. here) but that turned out to be a testing error as the PDF was later revised. If the report for the RM112 is correct then I agree the curve is unusual.

ex.treme
Posts: 64
Joined: Sun Jan 20, 2008 9:58 am
Location: Czech Republic

Post by ex.treme » Thu Feb 26, 2009 7:25 am

justyn wrote:Has anyone seen anything else like this? se.
Hallo!

Is Nxp (Holand factory Philips), but just reference pre-sample. Not for sale.(i have informed by email) NXp reference 250w - 92.97%
http://www.80plus.org/manu/psu/psu_repo ... Report.pdf - 92.97%

Another psu from FSP with interesting efficiency- not sure if is right>
FSP250-70MU - 92.63%
http://www.80plus.org/manu/psu/psu_repo ... Report.pdf

Compare with Dell Rm112 - 92.46-%
http://www.80plus.org/manu/psu/psu_repo ... us-Rpt.pdf

Nxp not for sale. The both i'm sure are. But i can't find when buy them.
:wink:

If someone want, send email their business center for ask product.

lobuni
Posts: 73
Joined: Thu Aug 23, 2007 2:33 am

Post by lobuni » Fri Jan 15, 2010 1:48 pm

I stumbled across this ebay listing
http://cgi.ebay.com/NEW-Dell-RM112-Opti ... 1005r16763
I wonder if it really has the same efficiency curve as shown in the 80plus tests.

edit:
oops I didn't notice this thread is so old.

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