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Dual rail 12V 16A vs single rail 12v 24A

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December 29, 2012 6:29:44 PM

Hi guys I am new :D  Have two PSU same brand, same 400W rated. One has two 12v rails 16A each other a newer edition has one 12v rail 24A. Which one will be better to use to run XFX HD 6670 low profile on Core 2 Duo 3.06gz system? One HDD and 1 DVD RW, a small Home theater system. Any advice will be much appreciated.
December 29, 2012 8:24:11 PM

You want to grab the one with the single 12v rail. It will provide stable, clean power to your system.
December 29, 2012 8:27:53 PM

Either would work, but I agree with DeusAres that the single rail PSU would be the better option.

-Wolf sends
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Anonymous
December 29, 2012 8:54:40 PM

do not get either.

any decent PSU will have 80% of its total wattage on the 12 volt rail.

so 400*.8=320 watts.

the second one with 24 amps is 288 watts - not enough. now the second one claims to have 2 16 amp rails for 384 watts. but since its made by the same manufacturer as the weak 12 volt rail PSU; i have serious doubts about its reliability. there are too many PSUs that can't provide it's labeled wattage.
Don't Be Surprised When Your Cheap PSU Blows Up

granted you have a very low wattage system that even a 300 watt PSU can handle - but its about quality and not quantity.
December 29, 2012 9:44:57 PM

Thanks for your replies, also most valued link Don't Be Surprised When Your Cheap PSU Blows Up http://www.tomshardware.com/reviews/low-cost-psu-pc-pow..." target="_blank">
I had a good read and one evening worth the whole term spend in college studying hadrware.
Looniam are you saying that my double rails humble PSU will provide better wattage for the system? How I can test my psu's without electrocuting myself, I have a multimeter.
The unit with double 12v rail is heavier than the one with single 12v 24A. Is heavier the better or is it heavier because it is an older unit?

I am leaning towards the single rail more recent PSU, it is a good brand designed in Germany I believe and I have not much to loose and I am lucky enough to afford to experiment with this setup.
Also I stumbled upon this link, http://www.tomshardware.co.uk/forum/306437-10-single-ra... found it is a very good read indeed.
More opinions will be much appreciated though. Power supplies are always a grey area and more understanding will bring more happiness in building and using our humble desktop computers. :love: 
Anonymous
December 29, 2012 11:35:26 PM

Logo said:
Thanks for your replies, also most valued link Don't Be Surprised When Your Cheap PSU Blows Up http://www.tomshardware.com/reviews/low-cost-psu-pc-pow..." target="_blank">
I had a good read and one evening worth the whole term spend in college studying hadrware.
Looniam are you saying that my double rails humble PSU will provide better wattage for the system? How I can test my psu's without electrocuting myself, I have a multimeter.
The unit with double 12v rail is heavier than the one with single 12v 24A. Is heavier the better or is it heavier because it is an older unit?

I am leaning towards the single rail more recent PSU, it is a good brand designed in Germany I believe and I have not much to loose and I am lucky enough to afford to experiment with this setup.
Also I stumbled upon this link, http://www.tomshardware.co.uk/forum/306437-10-single-ra... found it is a very good read indeed.
More opinions will be much appreciated though. Power supplies are always a grey area and more understanding will bring more happiness in building and using our humble desktop computers. :love: 
individually and some slightly more ethically manufacturers will stated the combined output in small print towards the bottom of the label:

that is a little better than some i have seen because the spec is in the table. but at first glance someone could assume that the 12 volt rail will put out 26 amps (13*2) and not the actual 18 amps (216/12). so realistically those are 9 amp rails not 13, a ~25% difference.

SO . .that dual 12 volt 16 amp PSU could very well and i highly suspect to be the same PSU with a single 24 amp 12 volt rail if you subtract the ~25% difference. (32*.75=24)" target="_blank">
it may not necessarily.

ok you have a PSU with a single 24 amp rail and another with two 16 amps rails. it would not be correct to assume that the two 16 amp rail will provide 32 amps of combined power. many manufacturers will label a maxim amount for the rail individually and some slightly more ethically manufacturers will stated the combined output in small print towards the bottom of the label:

that is a little better than some i have seen because the spec is in the table. but at first glance someone could assume that the 12 volt rail will put out 26 amps (13*2) and not the actual 18 amps (216/12). so realistically those are 9 amp rails not 13, a ~25% difference.

SO . .that dual 12 volt 16 amp PSU could very well and i highly suspect to be the same PSU with a single 24 amp 12 volt rail if you subtract the ~25% difference. (32*.75=24)
!