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Power supply help please

Last response: in Components
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September 7, 2010 11:51:43 PM

ok so, in despite of all the research i have been doing for the gtx 480s, ive come to realize, that its pretty easy to blow just about any power supply with sli 480s and an i7 overclocked to 3.6 ghz..

right now im using a PC power & cooling silencer 1000 watt power supply right now.. and from what i read, under load the gtx 480s in sli alone can tear my PSU a new one.....

SO to the point, i researched 1200 watt and higher power supplies, and lets be honest here, thats just ridiculous pricing range for 200 watts extra lol.

According to a friend who mods PCs for a living, 5 1/4" drive bay power supplies exist. He told me they go up to 650 watts and to be honest im thinking of buying one of those drive bay PSUs, but i cant seem to find any of them that can handle over 400 watts (cpu + mobo + hdds for this psu)

More about : power supply

September 7, 2010 11:53:05 PM

so i was wondering if anyone has seen a 400 watt or higher power supply, or knows of good 1200+ watt PSUs for under 150$ >.>
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a b ) Power supply
September 7, 2010 11:58:33 PM

1000 watt should be able to handle 2 480s and a i7...its getting close, but as long as its decent it should be fine.

http://extreme.outervision.com/PSUEngine

That says 754 watts. Factor in lets say 80% efficiency, and you would need 905 watts. Like i said, getting pretty close, but it should be able to handle it.
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a c 144 ) Power supply
September 8, 2010 2:14:45 PM

No. Factoring in efficiency means that the PSU needs 900 watts from the wall to supply 750 watts to the load. At 80% effiency and a full load of 1000 watts, the PSU will need 1200 watts from the wall.

A pair of GTX480's needs about 480 watts (40 amps) and the CPU needs about 120 watts (10 amps). Add on 20% for overclocking. That's about 660 watts at most. The rest of the system, unless you have a basket full of drives will use less than 140 watts. So, worst case, your system needs around 800 watts. Your PSU won't be running more than 80% of capacity.

You don't need a bigger PSU.
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a b ) Power supply
September 8, 2010 6:38:45 PM

jsc said:
No. Factoring in efficiency means that the PSU needs 900 watts from the wall to supply 750 watts to the load. At 80% effiency and a full load of 1000 watts, the PSU will need 1200 watts from the wall.

A pair of GTX480's needs about 480 watts (40 amps) and the CPU needs about 120 watts (10 amps). Add on 20% for overclocking. That's about 660 watts at most. The rest of the system, unless you have a basket full of drives will use less than 140 watts. So, worst case, your system needs around 800 watts. Your PSU won't be running more than 80% of capacity.

You don't need a bigger PSU.


Isnt that what i said? 900 watts for 754?
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a c 144 ) Power supply
September 8, 2010 8:51:32 PM

Not exactly.
ares1214 said:
That says 754 watts. Factor in lets say 80% efficiency, and you would need 905 watts. Like i said, getting pretty close, but it should be able to handle it.

Seems to me that you are saying the losses also come from the output. A PSU's power rating is based on its output, not the input power needed to produce it. As far as only the power rating is concerned, efficiency is meaningless.

if I misunderstood, apologies. :) 
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a b ) Power supply
September 8, 2010 10:31:10 PM

jsc said:
Not exactly.

Seems to me that you are saying the losses also come from the output. A PSU's power rating is based on its output, not the input power needed to produce it. As far as only the power rating is concerned, efficiency is meaningless.

if I misunderstood, apologies. :) 



I think we are saying the same thing, in difference ways, or saying the same thing, and it just sounding different :lol: 
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