PSU.Suitable output

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I'll probably be ordering my new PSU this week. I was going to get the largest Corsair unit 1000w which has great specs and gets good reviews but it is more power then I will need.

I recall reading something about it not being so good for the PSU to run underloaded all the time but not sure if I'm remembering it correctly.

So apart from the obvious $$ saving is there any other reason to not go for a higher powered PSU then you'll need?

All the (corsair) PSU's in my list are 80 plus silver rated but the 750 and 850 watt units have a 7yr warranty as opposed to a five yr for the 1000 watt unit.

There is $60 difference in price between the 850 and the 1000 and $100 between the 750 and the 1000. All are modular units. HX series.
 
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I know my requirements will be safely below needing a 1000w unit. 750 or 850 would suffice. just wondering if I were to get the 1000 unit does it do it any harm to never be worked very hard. It's just something I seem to recall reading somewhere but maybe I got it wrong.

However to answer your query either an i5 or i7 processor 4-8 gig of DDR3 memory. Single video card HD5770. 3xHDD
 
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I think I can safely say that whoever made the claim about under worked PSU, didn't know what they were saying. If this were to be an issue, I believe you would see specifications along the lines of Minimum Power Requirements as well as the Maximum.
 

Nibiru2012

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I think you're going way overboard here. Even high-end gaming rigs with two video cards in SLI or Crossfire usually need no more than 750 watts with two hard drives, 8 GB of RAM, etc.

Use the PSU calculators available at several websites. Newegg is a good start that Cliff gave you. The reason to use at least two calculators is to get a better idea of what you truly need. Plug in all the info and see what comes up. Then take that number and add a 20% cushion factor and you'll be good.

I am running three internal hard drives, a DVD-R/RW burner, 6GB of RAM, an ATI HD 3850 card, a wireless PCI card, 4 fans total, a high-end Gigabyte motherboard and an Intel E8400 3.0 GHz Core 2 Duo Dual core CPU.

My PSU is 550 watts and have plenty of room to spare!

Get a the correct sized PSU for what you have planned. Be sure it's rated at least as an 80 PLUS Bronze Certified unit.
 

TrainableMan

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I run a 550W with my single 5770. Now I know you like the velocorapters and I don't know if they require extra power but you will still probably be fine at 550, you definitely don't need more than 750 ... even for most dual GPUs that's enough.
 
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My existing PSU is also around 550w and doing fine but it's getting a bit long in the tooth now. I want a modular unit and the smallest is 650w, there's only about $50 difference between that and the 750w and if I got the 750w , well there's only $40 difference between that and the 850w. Soo,,, plus I like the idea of a 7 yr. warranty. They are all 80 Plus Silver grade.

I run 6 case fans and in addition to the hardware I've mentioned I'll have DVD & bly-ray drives and in internal video card. Want a bit of headroom in case something comes up later in terms of chips.

Maybe what I read was that a PSU is most efficient when run at about 60% of it's rated output.
 

Nibiru2012

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My 550watt unit is a modular but that's here in the States.

Get the 750 watt and you'll be fine. Even if you were stress testing your CPU and GPU at the same time you'd probably wouldn't go over 400 watts max.

But if you want to spend the extra bucks and so forth then go for it. On the other hand you could get the correct sized PSU and send the extra bucks you were gonna spend to the following new charity which I just established.

"The Nibiru2012 Society of the Everlasting Evangelical Assembly of Stargate Followers"

Then I could get that new Amazon Kindle I want!
 
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hmm, if Iwas a noble soul but I'm not.. I'm more for the "help Mychael spend his money on hardware addiction group" heheh
 

Nibiru2012

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hmm, if Iwas a noble soul but I'm not.. I'm more for the "help Mychael spend his money on hardware addiction group" heheh
Sounds like a malignant case of upgradeitis to me! Easy to diagnose, hard to cure.
 
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You only need 650w, 750w to be on the safe side. If you want the very best in PSU quality consider the Enermax Modu700+ Gold certified, or Seasonic's M12D 750w.
 
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I'm not familier with either of those brands. Not seen them for sale over here.
The Corsair PSU is 80plus Silver rated and with a 7 yr warranty.
My existing PSU is a Thermaltake 560w and has been very good but it's getting near 5yrs old now and is not a modular unit.
 
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Agreed, but Corsair is not the only brand. Try and look for those. They are at the top of the PSU pile so to speak. Seasonic also makes the PSU itself, the Corsair is actually made by Seasonic.
 
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Found the seassonic brand. That model is (from my usual supplier) $10 cheaper then the comparable Corsair unit but with only 5yr warranty as opposed to the Corsairs 7.
Specs otherwise seem to be comparable.
 
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Seasonic would have better voltage/ripple measurements. Is it the Seasonic M12D-II 750w? For a PSU, you need to find one that runs at 50% or so for peak efficiency (Silver in the case of the Seasonic) and one that has ripple measurements under 120mv, which the Seasonic (and Corsair) both achieve. In terms of quality, I'd go for Seasonic.
 

Digerati

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This question is, can running an overpowered PSU hurt anything? The answer is, no - except your budget.

It is important to note that a PSU will deliver only what is asked of it. So if a computer needs 400 watts, that is what the PSU will deliver, regardless if the PSU is a 500 watt PSU or a 1000 watt PSU. And the PSU will draw from the wall, only what is demanded of it, plus over head due to inefficiencies. So in this case, the PSU will draw from the wall 400 watts, plus about 20% or 80w for about 480 watts total.

Now no PSU is totally linear. That is, no 80% efficienct PSU is exactly 80% efficient across it's entire range. And usually a PSU is less efficient at the extremes - that is, when barely working, and when stressed near capacity. And I agree that 60 - 70% is typically that ideal range (but that is not set in stone). You do want some wiggle room, not only for future expansion and aging, but also so the cooling fan is not running full speed, maximum decibels, full time.

So IMO, if the 1000W PSU is way over powered, it will not be running at peak efficiency most of the time. This means, it will cost you more to buy, and cost you more in energy costs every day thereafter. I have a Corsair 750 and am real happy with it. I think you would be too.
 
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Both the 750 and the 850 are 80plus Silver rated with 7 yr warranty. I'd be happy with either.
 
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I doubt anyone keeps a PSU for 7 yrs, but the choice is yours, and both are built by Seasonic anyway. In prefer to buy direct from the manufacturer, so I would choose the M12D.
 

Nibiru2012

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I kept a PSU for over 8 years! It was an Antec and built very well. Still running today in a friend's second computer.

Seasonic, PC Power & Cooling, Corsair, CooolerMaster, Mushkin, Antec, OCZ, ThermalTake, FSP Group, Zalman and Xigmatech are all name brand top quality PSU units.

Be sure it's modular cabling which will help in routing only the cables needed and avoid clutter too.

In days gone by, the quality of the power supply was judged by its weight too, signifying quality transformer, heat sinks, filtering capacitors, etc., and it still holds true today.
 

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