Alonso wrote on Apr 21^st, 2009 at 11:11pm:



Use your head..

you would never buy a 36A single rail PSU for a video card that needs almost all of it because there is MORE NEEDED than just the video card... for the 2 RAILS its worse

However lets ASSUME you need 26A on that.. you use 2 rails at 18A to get it.. guess what, you are stuck because you CAN NOT have whats left over elsewhere.. you lose the use of 10A

Single rail means 26A goes to the job and the other 10 is available!

PSU selection is based on the total system need for each primary output

12v

3.3v

5v

VSB

You spec a PSU with 25% more power than you actually need so as components start to age they are covered and at the same time if you add something to a system you have all the power you need.. and then there is the THERMAL issue.. a 25% over spec'd PSU is going to run QUIET and COOL

you get what you pay for

If one is running a decent typical system and not clocking a 610watt PC Power and Cooling using will do just fine

If a Quad core and clocking is desired a PC Power and Cooling 750 is perfect

If one wishes a dual video card and clocking that must go up.. the PC Power and Cooling 850-1000 are needed depending on the cards and their needs


all are single rail PSUs and all will last for years.. I still have 2 PC P&C units from 1999 and 2001

a FULL LOAD efficiency rating of 82% or GREATER is what you look for with a single rail

NickN wrote on Apr 21^st, 2009 at 7:46pm:


I would agree that there is some "marketing hype" terminology when it comes to multi-rail PSU models. The vast majority of the population will go with what they've seen in ads or commercials and never bother to some research themselves.  It happens quite frequently with technology related products.  However, I wouldn't discount multi-rail models based on that fact as there are some advantages that multi-rail models have over single-rail.  (I have no bias towards either form actually.)  But to say that all single-rails are more efficient than multi-rails is sort of like saying all V6 engines are less efficient than V4.  Less efficient at doing what? A V6 engine truck is more efficient at towing and carrying heavy objects compared to a mid-sized V4 engine sedan.  If you try doing so with the latter, you will put more stress on the engine and burn more fuel.  Perhaps you don't like that anaology but to me it all depends on the person's usage of their computer and hardware setup.  Just my 2c.

NickN wrote on Apr 24^th, 2009 at 6:28pm:



The analogy that I gave above may not be to your liking as I predicted.  I used the V6/V4 engine comparison to make a simple point.  You may have a personal distaste for multi-rail PSUs citing its drawbacks, as if to say single-rails are superior in every way is an opinion and an opinion only.  Just like how I can praise the merits of a V6 engine heavy duty truck and say how EVERYONE should be buying V6 trucks makes absolutely no sense.  Our personal usage of vehicles can vary person to person; so can our usage of PCs and our hardware setup.

Now I can tell you're an interesting fellow Nick. I have no desire to get into a verbal pissing match to debate the pros and cons of multirail versus single rail - there are far more important things in life to get railed up about. No pun intended.  You're free to post as you will.  I have no desire to drag this continually with a person who is already dead set on his opinion. Have a good nite.

Maverick6901 wrote on Apr 24^th, 2009 at 10:53pm:


pissing match?

Please.. I would never lower myself to such a level


Instead if you would like to understand the real differences in the designs I suggest you may wish to start here..


         

P

o,i  
           i
=________  X 100
       

P

in  

which sets the stage for analysis by reducing both the multi and single unit to a ratio, expressed as a percentage, of the total real output power in the conversion process to the real power input required to produce it

From there we can continue through a series of formulas which can be used to compare our base ratio to our individual unit (multi and single) on equal systems and under equal load conditions.. This will fully address the electronic and mechanical design of each unit in the result. That will require a certified engineer with advanced degrees and years of experience in the subject to accomplish and fortunately for us one is in fact present.


When we get finished with that then I can explain how and why the result of those tests are different as I can then demonstrate both the electronic and mechanical reasons(s) for the loss from the single to multi rail unit in terms most can understand with support of formula which tie those descriptions to the laws of physics and will confirm the explanations.


And THEN we will discuss how the factor of TIME comes into play as components begin to degenerate within the first year of use. For that aspect of the analysis we will assume optimal climate control conditions for both units even though that is not a norm however it will further demonstrate the real Achilles' heel of the multi rail power supply unit which is exacerbated by modular plugs and termination points which should also be avoided with both single and multi rail power supplies and are another subject in themselves.


After we have finished our road of discovery you may read what Wingo posted above and although it could use a bit of refining it does represent the last factor involved...


Once we add it all up you will then have your answer as to why someone who is expereinced and educated in the subject would choose a single rail supply over a multi rail unit

Any power supply can be of good or poor engineering design, matters not if it is a multi or single rail unit. That is another factor which is completely out of the loop of our analysis however when one buys cheap (all too common even with what looks like a good PSU) they usually get what they pay for unless they know what they are doing and know the reputation of the manufacture so not only does the multi rail unit have many downsides.. a cheap multi rail unit takes that to the ηth degree.

If I was going to purchase a 'cheap' supply (which I never would) I would in fact want the 'cheap' single rail unit as that will not add insult to injury over time.





You asked a question... I answered it and answered it correctly

If you don’t like my answer and wish to argue it is nothing but an 'opinion' with someone who designed hardware for aerospace, I suggest you may wish to consider the person who is 'dead set' on his 'opinion' is you, sir

What I posted is not an 'opinion' although it was not technical in nature my comments are based in electronic/electrical engineering fact, not fiction or something I pulled out of the air.



I am however educated and trained to know marketing BS when I see and read it and regardless of their lack of technical explanation I thought perhaps there may be value in my initial comments so those who read them may in time avoid making costly mistakes.



Enjoy what you wish to use and believe is best.. Honestly, I could care less.