Power Supply Rail Question

Power Supply Rail Question · 12-05-2008, 05:50 AM

Assalam-u-Alaikum All,

Power supplies with single rails are better or the ones with multi rails. Is there any advantage of single rail over multi rail psu?.

fajoo24 · 12-05-2008, 07:36 AM

yar multi rail is better but usually the cheaper ones we get here r actually single rail divided into two or more rails.....so they aren't actually dual rail or more rails ones.....

separate dual or more rails psus r expensive ones like cm real power series (i think)....

ali.tayyab · 12-05-2008, 09:52 AM

Quote:

Originally Posted by ZED

Assalam-u-Alaikum All,

Power supplies with single rails are better or the ones with multi rails. Is there any advantage of single rail over multi rail psu?.

very very very debatable

the only reason many psu's come with multiple 12V rails is to meet saftey standards providing +60amps on one +12V rails isnt really safe!

pc power and cooling has a 750watt unit with one REAL +12V rails with mucho amps. no one makes better psu's than pc power and cooling, though they're owned by OCZ i am sure they still have their high standards

there are problems with +12V depending on their implementation:

1. Distinct +12V rails:
enemax +400watt liberty unit is a good example. each +12v rail is seperate from the other. it has 2 +12v rails. u gotta make sure u load balance equally between the two. the manual has some instruction on how to do this. many other units also have this *Feature*

2. Unified RAILS:
Corsair HX series is an example (atleast upto620). it has 3 (620 unit) +12v rails, but they act smart like one. no need to load balance.

3. Amps:
in multi rail setup the amps on Rails 2 and beyond arent 100% of the advertised value. it is usually:
amps 1+ 1/2amps2 or the likes.

thus u might have +20, +20 amp rails, they will probably act like +20,+10.

Smart rail psus (#1 avbove) quote one combined value for their rails usually. Corsiar advertises about 54amps (or is it 60?) for their rails 1,2,3 on the hx620

also there are many articles on the net which tell u that single rails are better than one, but not many psu makers employ single rails.

hope this helps

if u're in the market for a psu read reviews here:

hardocp

this is probably the best site i've seen for psu reviews. anandtech also has a very good section and testing methodolgy paralleling that of hardocp

ZED · 12-05-2008, 09:53 AM

Actually this question come into my mind because PC Power & Cooling site listing nagative points of multi rail psu like if your CPU use 7A and there are 17A in rail remaining 10A will be wasted because it can't be used by the rest of system.
Another expamle was if your gpu requires 20A and rail is limited to 17A it will shut down the psu b/c of Over Current protection.
All this was annoying for me because the psu I choosed for my system is of 3 rails, it's Antec NeoHE 650 with blue led.

ali.tayyab · 12-05-2008, 10:01 AM

Quote:

Originally Posted by ZED

Actually this question come into my mind because PC Power & Cooling site listing nagative points of multi rail psu like if your CPU use 7A and there are 17A in rail remaining 10A will be wasted because it can't be used by the rest of system.
Another expamle was if your gpu requires 20A and rail is limited to 17A it will shut down the psu b/c of Over Current protection.
All this was annoying for me because the psu I choosed for my system is of 3 rails, it's Antec NeoHE 650 with blue led.

word of warning antecs are notorious for compatbility problems with many mobos

now that, that is out of the way, if u buy a smart multi rails psu u're good to go. they treat multi rails like one and thus if one rail over loads it transfers load to another rail

if u can get corsiair HX series. they have the best reviews that i've read anywhere on the web!

mave_3 · 12-05-2008, 02:08 PM

Multi rail is always better then the single rail in simple words..
it helps to balance the load.
and so in this way it transfers the load to the second rail and in some to the 3rd rail...
to balance the load...
and to keep everything running smooth!!!
soo a multi rail power supply is safe and better than a single rail PSU!!!!

ZED · 13-05-2008, 11:46 AM

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