What's the deal with single rail power supplies?

[flowerpower]

I would like to know whether single rail power supplies like the PC P&C PSUs are better than their multiple rail counterparts and why?

 

[wolfram]

Well, PC P&C PSU's are always extremely good and reliable. You really can't go wrong with them.

But some of us prefer dual rail PSU's because they offer more stable voltages. Also, "normal", dual rail PSU's are considerably cheaper than any P&C one

But if you have the cash for a PC P&C PSU, go for it.

Regards :wave:

 

[flowerpower]

Yes, i have the cash for it, i was intially thinking of picking up a Silverstone Zeus 850W, but now i'm considering PC P&C Silencer Quad 750 or Enermax Galaxy DXX 850W because they are supposed to be quieter than the Zeus which gets somewhat loud at load.It is difficult to decide between the 2, i like the Galaxy a lot because it's modular and has 8 pin PCI-E connectors for the upcoming R600/G90 cards, but the Silencer is also great. I plan to run 2 8800GTS in SLI eventually so i will need the power of such PSUs thus the question about single rail. Can you give me a example of or recomend a dual rail PSU that will run my system + SLI setup?

 

[LinkedKube]

You're concerned about the power rails for g90 cards, but you plan on upgrading to g80sli, If you already dont have g80sli then why are you worrying about power rails for g90 cards

 

[flowerpower]

Because it would be nice to have a futureproof PSU, i don't want to buy another when i upgrade to G90, does that make sense to you?

 

[wolfram]

How much can you afford?

 

[sllewe]

When it absolutely positively no questions asked has to be powered.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817703007

But on a more serious note, I can never put any brand of PSU higher then PC Power and Cooling. I have used their products twice. Both rock solid. But Enermax are just right up there as well. The modular design is nice (although I would like to see if there is any power variation/loss with it) The Dual rail is also a plus.

 

[flowerpower]

Thanx for the tip AtK SpAdE! To answer wolfram's question i can afford any of the power supplies i was considering, probably no more than $300.

And a little update: PC Power & Cooling updated the Silencer Quad about 10 days ago now it has 2 6 pin PCI-E & 2 8 pin PCI-E.

 

[JimShady23]

Well

I own a silverstone zues 650, the thing is a monster. It has more than enough power for my needs and runs flawlessly. It has 4 rails of +12v power.

I would imagine that there is nothing that that 850watt model could not handle. However as you said, they are rather loud. It is probably the loudest part of my system.

This is due to the fact that it has only 1 80mm fan to keep it cool.

 

[flowerpower]

I decided to get the Silencer Quad, in part due to to the fact that it is futureproof. It also has a single 80mm fan like the Zeus, but all reviews i've read describe it as quiet or somewhat quiet so it can't be that bad. I much rather have a rock solid PSU and if it does get a little noisy under load so be it.

If anyone is interested in getting the revised version with the 2 8 pin PCI-E they can purchased at their site, i doubt that other retailers have it in stock yet since it's so new.

 

[wolfram]

That was a good choice Enjoy it!

 

[Grafficks]

In case anybody else is wondering, there's a reason why the PSU industry leader (PC Power & Cooling) is now making only single-rail PSUs:

8. ARE MULTIPLE 12-VOLT RAILS BETTER THAN A SINGLE 12-VOLT RAIL?
With all the hype about multiple 12-volt rails (ads claim that two rails is better than one, five is better than four, etc.), you’d think it was a better design. Unfortunately, it’s not!

Here are the facts: A large, single 12-volt rail (without a 240VA limit) can transfer 100% of the 12-volt output from the PSU to the computer, while a multi-rail 12-volt design has distribution losses of up to 30% of the power supply’s rating. Those losses occur because power literally gets “trapped” on under-utilized rails. For example, if the 12-volt rail that powers the CPU is rated for 17 amps and the CPU only uses 7A, the remaining 10A is unusable, since it is isolated from the rest of the system. ...

Apparently, single-rail PSUs are making a comeback.
More HERE.

 

[wolfram]

Good find Grafficks.

Anyway, most PSU's have dual +12V rails, and they work pretty well