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psu question

Bolerus

Bolerus

Bolerus

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Joined
7 Jul 2006
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Stoke on Trent
sorry if this has been asked before, but I have looked around and not quite getting the answer

I am about to buy a gtx 480 from a friend.

I looked at a few power usage calulators, and in a nut shell, they all seem to agrea i need a 650 psu (i will go for at least 750 to be safe)

the problem i am having is... I have read somewhere that the 580 needs 42a on the rails.

there dont seem to be that many psu's with that much ampage on a single rail

so, my question is.. considering that this card requires 2 8 pin conectors.

if i get a psu with lets say 30a per rail, and then use 2 seperate cables for the 2 8 pin conectors, will that achieve the purpose.

also how do you tell if a cable is on a the same rail as another.

is there some kind of understanding psu's for dummies link?

i have seen some psu's with '1 rail for efficient power distribution' offering 60ish amp on the rail, is tha the way to go?

in a summary......help !!!!!
 
Buy a Psu with one rail with no line limits, (most PSUs only have 1 true rail anyway, but have load limits on separate lines, which is what most people confuse as separate rails).

I'm pretty sure most if not all Seasonic Branded and re-branded PSU have no line limits. And a lot of other high end brands are the same. Aways check a decent review to make sure.

A "good" 600 W PSU should be ok for a GTX 480/580 system.
 
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600? really? that surprises me

the lack of response to this thread make me feel a little bit better, it would seem im not the only one who dosent fully understand all the BS around rails.

I have pretty much decided to discard any PSU with multi rails and to buy one with only one rail (current fave is a thermaltake 850 watt for around 90 squids that has one 72a rail)
 
Not that there is anything wrong with a PSU having pesudo rails(limited lines), having no limits means you won't have to worry about exceeding them. :)
(Naturally don't stick everything on one cable using adaptors. :p )

The gtx 480 is rated at 250 , even if you allow 300 W to be safe, with 600 W on the +12v (50 A) is plenty.

If you do go for a decent 850 W, you could probably run SLI 480s. ^^

If you don't mind not having Modular this XFX Pro 850W looks good for the price.
http://www.overclockers.co.uk/showproduct.php?prodid=CA-005-XF&

The thermaltake 850 you are looking at is likely to be more than fine too.
 
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IF you get a PSU with multiple rails then each 12v cable should normally be from a separate rail. So it wouldn't matter that much really. The 42A doesn't have to be on a single rail. If you're using 2 connectors on two seperate rails with less than that, but where it adds up to 42A min you'll be fine.

but yeah it's just easier to stick to single rails PSUs.
 
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