Antec BP550 Plus and 9800GTX+ sli system

michaelrm1256

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My Kingwin 1200watt died.
I had to go get a PSU asap to continue gaming and the only place to get one around here was Staples.

I'm trying to figure out if this Antec bp550plus can Safely run my 9800 gtx+ in SLi.

The PSU has 12v rail one 22amp 12v rail two 22amp and 12v rail three at 25 amp.

Its saying max combined wattage from all 3 rails is 444. How do they get this number?
25 x12 =-300
22x12 etc ....It doesn't add up.
444/12 is 37 amp right?

Btw from charts I've seen the actual amp draw on the 9800gtx+ is only 10.5 amp at max load. http://www.tomshardware.com/reviews/geforce-radeon-power,2122-6.html

Nvidia says 24 amp. I understand they are over stating for the usual reasons.

So since I am thinking the real amp limit is 37, running 9800gtx+ in sli with a Core i5 760 one Sata drive and 8gb ram on like 2 fans I should be fine.
I have been running this for a few days at all seems well under full load in benchmarking and gaming.
What do u guys think?
 
Solution
It will be fine.
Multiple PSU rails are almost never strictly additive. Usually, a single rail is broken up into current-limited sub-rails, such that the sum of all the rails cannot exceed a total, but each rail is able to go well over a "1/n" limit.
It will be fine.
Multiple PSU rails are almost never strictly additive. Usually, a single rail is broken up into current-limited sub-rails, such that the sum of all the rails cannot exceed a total, but each rail is able to go well over a "1/n" limit.
 
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michaelrm1256

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so Basically exactly how those amps are distributed on those 3 rails is a bit of mystery? Do I have 37 amps total or no?
AND MEGA thanks for the help Bros!!!! That was freaking fast!!
 

michaelrm1256

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Does the 1/n limit mean that it can go over the 22amp stated limit on 12v rail one? Im not quite getting it
 
Hypothetical example: A PSU has three +12 rails. The total +12V power is 40A, or 480W. One third of 40A is 13.3A, or 160W; but each rail is current-limited to 22A, or 264W.
This means that any single rail may be loaded up to 22A, but the total of all three +12V rails may not exceed 40A.
 

michaelrm1256

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understood thanks for your time