Solved Help me choose a new power supply

Emachines Emachines et1331g-03w desktop...
May 13, 2013 at 10:58:45
Specs: Windows 7, athlon II x 4 645/6gb ddr2
I am building a new gaming rig and i need some input on power supplies. In the past i have used the Seasonc X660 and X750 and those were great. I'd like to get 2 used gtx 580s from ebay, hoping for $200 each, may be dreaming a bit here. Or i could buy 2 new gtx 660s. I know the 660 will use less power. Will an AX850 or X850 be suffiecient for 2 580s in sli? I am also taking into consideration that the new 780 will be out this month, but i have no idea of the power requirements. I guess it would be the same as the titan.

Now lets talk brands. ive heard that seasonic and corsair are really the same.
Ive also looked at the XFX 750pro, and it has the same hybrid fan controller.
Im not sure if i need an 850 or 750 watt.

Proposed specs of build:
CM HAF 912
2 X 4 GB HYPERX @ 1600
3 FANS-1 120mm and 2 200mm red led
580 SLI, 660 SLI, GTX 780

My last rig had the seasonic X660 with 2 evga 448 classifed ultras (GF 110) overclocked to 970 mhz and the cpu at 4.0 ghz. The power supply had no problems with that, and yes i was quite surprised. But that was only for running benchmarks. During normal use, everything was at stock speeds.

Ok so whats the difference between the X650 and X660?
difference between X750 and X760?
Any differences in the 850s; seasonic, corsair, xfx?

My gut tells me to get an 850 and let it go at that.
Newegg had the XFX 850 on sale for $99.00. was that a closeout of a discontinued model?
I believe a 3 of these brands are really made by seasonic, but this time i wanna save a little money. I dont automatically buy everything from newegg as i have in the past.

Last January, I bought 2 sticks of kingston hyperx ddr3 1866gx (2 x 4gb) for 49.99. that same memory today is $92.00. What the hell happened with ram?

Enough for now and thanks for any help you may give.

ignore the specs for the emachines, thats just my regular desktop.

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✔ Best Answer
May 14, 2013 at 08:06:51
That unit has a $20 rebate on it right now. You can't go wrong with buy 80 gold. To me, the 5 year warranty makes me feel comfortable with any PSU that carries it.

May 13, 2013 at 11:18:51
Check online resources like this.
Only recommendation I'll make is 80+ and two rails.
Best of wishes!

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May 13, 2013 at 13:06:43
The preferred type of PSU is one with a SINGLE +12V rail of sufficient amps to run everything with a cushion.

AMD processors are going to be 125W or less, = 10.5A or less @12V.

GTX 660 cards pull 140W max each, = less than 12A@12V x 2 = 24A

35A@12V plus RAM, drives, board current should be no more than 10A@12V.

The PSU linked below has a single rail with 53A@12V. That should be more than enough for what you are building.

Some of the power is pulled from the 5V & 3.3V rails too.

Can't beat the price. Good reviews and 5 year warranty.

See the other links for more help.

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May 13, 2013 at 13:46:48
I used the power supply calculator on newegg. 2 gtx 580s would need 928 watts so thats out.

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May 13, 2013 at 13:59:38
i may have to rethink this whole thing. especially two cards vs one.

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May 13, 2013 at 15:58:02
I don't know where you get those numbers. The GTX uses 1 - 6 pin & 1 - 8 pin auxillary power connector. The chart linked below shows with that configuration the max. power consumption can't be more than 300W. 300W @12V = 25A.

A 660 complete test system only draws 300W. See the nvidia link below that shows the 660 draws 140W max.

The two cards are about the same price.

You don't need 750W/ 850W PSU, even in SLI.

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May 13, 2013 at 16:14:34
From the Nvidia website; GTX 580, a 600 watt power supply is recommended for one card. I think ill skip the 580. i may skip the whole thing. thanks as always.

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May 13, 2013 at 20:21:09
That is minimum complete system requirements and that takes into account overrated cheap power supplies with lower available 12Volt amperage. The second card would not add as much as you think. with a single 580/680 or two 660's, the quality 650 Watt should be fine and if you want to leave enough headroom for two of the 580/680's, then a quality 750Watt to 850Watt should be more than enough.
Wen we say quality, we are referring to a single 12Volt rail, 80% or greater certified efficiency, Active PFC, a name brand, a 3 to 5 year warranty, and most of the available amperage on the 12Volt rail.

You have to be a little bit crazy to keep you from going insane.

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May 13, 2013 at 20:44:28
Just to add a comment. I think SLI & crossfire are a waste of money. As you are learning, the power supply becomes an issue, the boards cost more and you don't get double the performance.

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May 13, 2013 at 22:59:17
I have always bought Gold rated power supplies, never any junk. They all have single 12 volt rails. I had a corsair ax 750, seasonic x750, and x660. the last one running 2 gf 110 cards in sli. i didnt think it would do it. XFX has a 750 watt modular gold that looks exactly like the seasonic model with the hybrid power switch and exactly the same cable interface. im pretty sure its made by seasonic, but the price is $129.99

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May 14, 2013 at 08:06:51
✔ Best Answer
That unit has a $20 rebate on it right now. You can't go wrong with buy 80 gold. To me, the 5 year warranty makes me feel comfortable with any PSU that carries it.

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May 15, 2013 at 16:10:18
I got this one.

i thought it was the best choice for the money and quality plus has enough power for future needs. as for now, i will take the athlon quad core and gtx 550ti out of the emachines and set it aside. i dont have anymore money left in the budget for the cpu or video card. i do think a phenom 965be and gtx 660 will be ok.
so here is the build:

cooler master HAF 912 case
gigabyte 990fxa-ud3 motherboard
kingston hyperx ddr3 1600 2 x 4gb
xfx 750 gold modular power supply
seagate 1 terabyte hd
liteon dvd drive
windows 7 home premium-already have a disk
athlon II x 4 645 @ 3.1ghz
evga gtx 550ti

unlike the emachines, i will be able to overclock the cpu on this board. 3.5ghz is good.
this will be enough to get me started. i also plan on adding 2-200mm red led megaflow fans. one in front and one on top and i already have an awesome cpu cooler, but wont need it with the athlon. i can get a phenom for $79.99 at microcenter and overclock it to 4.0ghz with the cpu cooler i have. not sure about getting an FX8350. they cost a lot and draw a lot of power. id have to say my favorite video card of all time is this one.

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May 15, 2013 at 16:25:05
Did you get the rebate slip off the same screen as your link above?

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May 15, 2013 at 16:39:25
You know, of all the stuff ive bought in the past 5 years, I have never sent in a rebate.
I keep the barcodes on the box. For example, if there is a problem in the first 30 days, newegg will exchange it. BUT, if the barcode has been removed for a rebate, they will not take it back. i would have to deal with the manufacturer, which is something i never want to do. I never buy an item because of a rebate. i want my money in the price going in. I feel good about the price on this power supply, even without the rebate.

Thanks everyone and Cheers

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