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High efficiency power supply low wattage system

Last response: in Components
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September 22, 2011 12:09:49 PM

Hi, I'm looking for high efficiency power supply to build low wattage computer which will include about 18 watt max CPU (AMD E450), 3 HDD (WD 500GB 7500RPM, WD 3TB 5400RPM x2), 8GB memory, 1 extra Network card + 1 Wireless network card, TV card.
I guess that power requirement of full system should not over 60watt (or maybe little bit more).
I need to find PSU which will supply enough power and in the same time will not waste the electricity on the low system load (while whole system will around 15 watt).
What are the products that can provide me with those requirements or some other solutions that can be applied?
September 22, 2011 1:21:49 PM

http://www.newegg.com/Product/Product.aspx?Item=N82E168...
It's reputable, 80+ certified.
If you wanted to get more efficiency you could go with a super cheap 150wattish power supply because power supplies have the most efficiency at about 50% load, even so I think that an earthwat from antec will get you better results and be more stable.

Have a nice day!
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a b ) Power supply
September 22, 2011 1:38:18 PM

Generally, speaking you want PSU that has the "80Plus" certification which basically means at any load the minimum efficiency will be 80% across the board.

"80Plus" is usually accompanied by a metal. The lowest would be Bronze for the minimum 80% efficiency. The highest would be Platinum which I beleive are a minimum of 92% efficient. The higher the rating the more expensive the power supply will be. I've only seen the 80Plus Platinum certification on highout power supplies so you will probably want to pass on those.

Which power supply you ultimately want to buy depends on your budget. I generally only Seasonic PSUs because of their consistant high quality rating and reviews. They are more or less unmatched, but that can mean you pay a slight premium for thier PSUs.

Seasonic also manufactures PSUs for other brands. All XFX PSU are made by Seasonic. Corsair, Antec and PC Power & Cooling have certain models that are made by Seasonic.

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September 22, 2011 2:20:32 PM

my understanding is that just to get basic 80plus rating a PSU must be 80% efficient between 20% and 80% load (and those bronze, silver, gold, and platinum ratings step efficiency up further), but that could also mean that at under 20% or over 80% you're not guaranteed to be 80%+ efficient.

i've got an antec earthwatts 430 on my atom 330 bit-bucket system. it idles at around 20W but i highly doubt i'm still getting 80% efficiency at such low load.

my suggestion would be to determine what the minimum wattage your system will actually use while at idle, then find a PSU with low enough wattage that even with the PC at minimal load it'll be demanding at least 20% from the PSU.

ex. if PC is 15W at idle then a 75W PSU would be ideal.
or if PC is 25W at idle then a 125W PSU would be ideal.

this is the lowest wattage PSU that's still 80plus that i find on newegg.

since power efficiency is a concern for you keep in mind a high efficiency PSU is only part of the solution, you'll also want low power components. low power HDD's, one stick of RAM instead of multiple sticks, low power NIC, etc, will likely make more of a difference than upgrading to an 80plus PSU would at such low loads.
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September 22, 2011 2:25:23 PM

Thanks for replies, but I see they are going wild.
I understand that more efficiency can be reached when the system load is above the 50% and highest are at more than 80% load, but proposals of HIGH WATTAGE power supplies is not suitable to the system that I described.
Pay attention, I'm talking about system that is consuming VERY LOW POWER, about 10-40 watt. That means, using of PSU above 100 watt will never give me good value. "80Plus" proposed models starts from 250 watt and higher.
The problem is here: than higher max wattage supports PSU then higher loose of power will be at low load (keep in mind those 10-40 watt of system load). That means I need very low wattage PSU at max 60-70 watt.
That was the question, I need the best PSU at 60-80 watt which will give me a reasonable power loose at 10-40 watt max.
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September 22, 2011 2:29:19 PM

-> branden
Thanks, that is the much more close, but it still have a 220 watt. Some thing less powerful? By the way, this form factor is better to me.
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a b ) Power supply
September 22, 2011 3:58:14 PM

As far as PSUs are concerned, be informed. Before you buy any PSU read accurate, objective PSU reviews at reputable sites such as www.jonnyguru.com or www.hardwaresecrets.com on the EXACT model PSU that you are interested in as some brands have good and poor quality PSUs.

You can also get an accurate rating of how much PSU power is required for your current or future system at the PSU calculator link below. Once you know the total PSU watts required then you need to confirm that the 12v rail has enough amps. to support your Vid card(s) and the rest of the PC system.

There are several websites that show the Vid card power consumption in watts. Divide the watts by 12 to determine the amps. required on the 12v rail(s). Add 15 amps for the rest of the PC on the 12v rail and you now know the Minimum total 12v rail amps required under full load. It's best to have at least 5-10 amps. reserve on the 12v rail available under full load so the PSU is not loaded to 100%.
It's also worth noting that people often misunderstand the 80% power rating. This is a rating of the PSU's energy efficiency not it's output. 80% plus PSUs use less grid power to produce the same PC power. If it's 80% Bronze, Silver or Gold the cost savings on electricity is pretty small between Bronze, Silver and Gold unless you are paying very high rates for electricity so any 80% rated quality PSU is fine even if not Gold. For those who leave their PC on 24/7 a quality 80% PSU is a good investment.


http://extreme.outervision.com/psucalculatorlite.jsp

http://www.guru3d.com/article/geforce-gtx-560-ti-sli-re...

http://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_5...



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