How to Pick the Right Power Supply

Now I have read through this and am still have a query that I did not see an answer for (I probably did but....) is then a modular PSU in reality a multiple 12v+ rail PSU if there are more than say two module power sockets carrying 12v+ in addition to the main cable that has the 24pin connector on it and flying cables?

I used a single rail Corsair HX 650 on the last build going on what Scott Mueller stated in his build video and book about having a single rail PSU as being the preference - against a twin or multiple 12v+ rail unit.

I am just curious because if the modular PSU is a single rail then the modules would have to be supplied by the main rectification unit (internally connected) that supplies the flying cables as above making it as stated by Corsair a single 12v+ rail PSU. So in essence making it modular just saves on more flying cables having to be tucked away unused.

Thanks ignazatsonic I was just curious as I have built power supplies for different purposes in the past and all have been "single rail".

My only "concern" was that if one of the twin rails went south then it would leave half the machine without power or worse catch fire. So a single rail would in fact make more sense in that eliminating problems is that much easier should the PSU be the fault:)

Yep I get your point I was just thinking about those that are in fact two rectification units in one PSU and I suppose one could keep going back to the transformer/s itself / themselves and in that case they would probably be the prohibitively expensive ones - if my experience of building power supplies is anything to go by.

Transformers capable of putting out that sort of current always were very pricey and I am talking of even ones that would put out 15v+ at 5A from a particular voltage tapping / winding.

Most of my reason for the query too was that I am having to choose between buying a new single rail PSU and a used but in good condition twin rail Coolermaster I already have for a friend. :)

gazz9496 said:

quality of psu is the most important factor.

you can usually rely on the usual brands for decent quality, antec/coolermaster/thermaltake/corsair/seasonic/ocz i'm sure there are others.

power requirements, get more than you need. why? well you may be planning to update or upgrade your machine and assuming you bought a quality psu it will probably last for a while and if you bought a 750w where 550w would have been enough you have wiggle room for upgrades within your platform without having to shell out for yet another power supply.

never skimp on your power supply, if it seems to cheap chances are it probably is.

Yeah Gazz I was going to reply to ignazatsonic re this last night but was called away.

In all reality it does come down to quality and I might just get a 480W Corsair for the friend as he is into graphical stuff and I am now real sure the older Coolermaster I have as good as it appears may let him down.

So all up better going new I mean if the mains winding burns out in anything then it's not going to work however many rails one has on it.

But I have to say this has been a real learning experience all the same as my supply building was generally aimed at chargers and electroplating supplies.

Thanks for the time and patience of all:)

Proximon said:

I maintain a PSU guide at the TH forums, where I try not to get too technical. There are many of the same links and more as well. Also a glossary, and a link to a small list of PSUs often recommended.
Computer Power Supplies - A Guide - Power-Supplies-PC-Cases-Case-Mods - CPU-Components

Not that you can see it right now, forum is down temporarily

Hiyya and welcome Proximon that's a nice link you have added - and have saved it to favourites:)