Power supply newb

lingenmi

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Jun 8, 2012
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10,510
Just purchased the below system and I'm considereing adding a second Nvidia GTX 570 card so that I can run 3 monitors in Nvidia Surround mode. As you can see the machine has an 800W power supply. The Asus power supply calculator recommends 1050W at least if I add the second card. So.....the question is just how risky is it to stay with the 800W power supply? Thanks to all who offer some advice!!!

System Configuration:
Chassis Model: Corsair Obsidian 550D
Processor: Intel Core i7 3820 3.6GHz
Motherboard: ASUS Sabertooth X79
System Memory: 16GB DDR3 1600MHz
Power Supply: 800W Corsair GS (Dual SLI Compatible)
Hard Drive Set 1: Operating System: 1x (120GB Solid State (By: Corsair) (Model: Force GT Series CSSD-F120GBGT-BK) (SATA 6Gbps)
Hard Drive Set 2: 1x (120GB Solid State (By: Corsair) (Model: Force GT Series CSSD-F120GBGT-BK) (SATA 6Gbps)
Optical Drive 1: DVD-R/RW/CD-R/RW (DVD Writer 24x / CD-Writer 48x)
Internet Access: High Speed Network Port (Supports High-Speed Cable / DSL / Network Connections)
Video Card(s): 1x NVIDIA GeForce GTX 570 2.5GB (Includes PhysX) (EVGA 025-P3-1579-BR)
Sound Card: Integrated Motherboard Audio
Extreme Cooling: H20: Stage 1: Corsair H60 Liquid CPU Cooler (High-Performance Edition)
Chassis Airflow: Standard Factory Chassis Fans
CPU Boost: Stage 1: Overclock CPU 4.0GHz to 4.4GHz <b></b>
Graphics Boost: Overclock the video card(s) as much as possible with complete stability
 

lingenmi

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Jun 8, 2012
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10,510
Thank you Sir! Hence my confusion. I have found many articles and many calculators, some of which indicate that 800W is fine and some that recommend more. I am no expert. Thanks again!
 

dassix

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May 31, 2012
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Very nice setup! Not that you posted a thread on help with your build, however...I finally got into getting dedicated sound cards, and have had nothing but positive things from it.
 

ram1009

Distinguished



Risky isn't the word. Stupid is more like it. why would you risk starving such a nice system with something so basic as a undersized PSU? Personally, I never run a PSU past 50% of capability. It's an investment that pays dividends over time. Stressing a PSU is one of the worse things in any electronic device including computers. My advice is to buy the largest quality PSU you can afford. You won't be sorry.
 

lingenmi

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Jun 8, 2012
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Stupid would also be expending resources without clear benefit or necessity. Which is why I have asked the question. In order to assess the possible effects of different variables.

You say risk starving such a nice system but you provide no evidence that it is starved. Evidence is what I am seeking.

However, your reply is still appreciated and considered. You would not have posted if you didn't think it would overload an 800W power supply.
 

dassix

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May 31, 2012
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I would also look at the individual requirements for GPU ect, in terms of amps. "For example if the card needs 10A, then 10x1.25 is 12.5Amps minimum on the single or combined +12V rail/rails."

Watts is good to look at for general system requirements, but specific components of the system need to also be analysed.
 

ram1009

Distinguished



Not necessarily true. I would need to do a calculation to say something like that. The benefits of an oversize PSU are seldom immediate. Think of it this way, would you run your car engine in first gear all the time? Certainly not. You would wear it out prematurely although it would work fine for a while. The same is true of a PSU. I can provide no hard evidence of this, you'll just have to use your intuitive common sense. I've been specifying commercial power supplies for many years without any failures. Of course any part can fail any time so there are no guarantees, however oversizing a PSU removes stress from the failure equation.
 

Bad example, car engine has moving parts PSU's don't. Engines last longest and are most efficient run on 80% load.