PSU 12v rails help with gigabyte gtx 680

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zink1701

zink1701

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I have a Antec Truepower 650w PSU and it has 4 12v rails. 2 of them are 22A and the other 2 are 25A. I want run a gigabyte gtx 680 but will running off 1 25A rail be enough or will i have to use 2 12v rails to power the card? Also I am not sure how the rails work will each rail produce the Current it says or is there a maximum current for all rails, If they are all added together then the PSU will give nearly 100 Amps? that dont sound right to me. If someone could tell me how it works that would be fantastic. Thanks in advance for any help on this.
 
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Antec has several "truepower" 650W units (New, trio, etc.) so I'm not sure which you have. I'll speak in general terms.

Most "multi rail" PSUs are really single rail. What they do is use an "OCP" (Over Current Protection) circuit to limit the output/current of each "rail". For example, the "trio" is listed as a three rail unit but Jonnyguru says it isn't so.

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story2&reid=1

This is basically a protection thing. As JG has talked about as the big PSUs (1600W+) have come out having a PSU with the ability to power ALL of that through something that shorts out is a fire hazard. This issue doesn't exist with a smaller 650W unit but you want OCP on a larger one.

So what to do...
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JackNaylorPE

JackNaylorPE

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http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-680

Requires 500 watt PSU and two 6 pin PCI-E cables. You simply connect 1 cable from each rail even of the rail is capable of handling two in order to provide load balancing which will provide more stable power to all components

Max card draw is 195 watts, 97.5 per cable *.
97.5 / 12 = 8.13 amps

* NOTE: The PCI-E PEG spec called for a rating of 75W for PCI-E 6-Pin cables and 150 W for PCI-E 8-Pin. Cables and sockets haven't been compliant with this standard since the days of the 4xx cards

http://www.jonnyguru.com/forums/showthread.php?t=7212
 
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4745454b

4745454b

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Antec has several "truepower" 650W units (New, trio, etc.) so I'm not sure which you have. I'll speak in general terms.

Most "multi rail" PSUs are really single rail. What they do is use an "OCP" (Over Current Protection) circuit to limit the output/current of each "rail". For example, the "trio" is listed as a three rail unit but Jonnyguru says it isn't so.

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story2&reid=1

This is basically a protection thing. As JG has talked about as the big PSUs (1600W+) have come out having a PSU with the ability to power ALL of that through something that shorts out is a fire hazard. This issue doesn't exist with a smaller 650W unit but you want OCP on a larger one.

So what to do? Don't worry about it. They are artificial limiters that only kick in to prevent shorts. It's pretty hard to trip the OCP without doing something odd. You should just be able to plug in the GTX680 and not worry about anything. If it doesn't power up, try using a 6pin plug from the other set of wires.
 
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