Confused about Dual Rail thing

[Beliar]

Is it true that dual rail psus are not worth buying? I can't decide between OCZ Powerstream 420, Enermax 495AX Dual rail (12v1@18A, 12v2@16A according to newegg, 18A according to official website), Fortron Blue storm 500 Dual rail (12v1@15A, 12v2@15A)

All of the reviews i could find about dual rail units were positive. But some of the users on these forums speak badly of them. I need help..

The unit is going to power these :
DFI Ultra-D
AMD a64 winchester 3200+
OCZ 3200 Plat rev2 2x512
BFG 6800 GT OC
2 IDE hdd's
2 Optical Drives
Audigy,
Fans, etc.

*I'm going to overclock, planning to get 2,6-2,7 ghz.

Thanks.

 

[TransientBen]

You can go wrong with a quality unit of any sort. I'm not sure if you'll be able to get a 24-Pin PSU -without- dual rails, so may as well invest in a decent one. I'm guessing Newegg says the Enermax you're looking at has the Amp variation because the 12V rails have a combined limit of 32A. Their own picture of the ratings label on the PSU reads 18A/18A.

I looked long at hard at the Fortron Blue Storm (400W), but after seeing a few not-so-shining reviews, I wasn't quite as confident. I picked the Enermax 425P - All independent rails, up to 18A on each 12V (29A combined), plenty of connectors and good efficiency. But then, I'm no overclocker, so maybe something more powerful is in order for you.

 

[symbol]

Originally posted by: TransientBen
I looked long at hard at the Fortron Blue Storm (400W), but after seeing a few not-so-shining reviews, I wasn't quite as confident.

What was the overall criticism of the 400w blue storm?

 

[Navid]

I am in the market too.
This is what I think.

Let's say you have a dual-rail with 15A capacity on each of the 12V rail. This will work fine if you never need more than 15A from either of the two rails. The problem is that if you draw too much from one rail you may already have a problem even though your total may be less than 30A.

In comparison, if you get a supply with a single 30A rail, you will have nothing to worry about as long as your total load is less than 30A.

The only advantage of two rails is that you can isolate the components by placing them on separate rails. But, I cannot think of a reason why a home user may need isolation between components.

For me, a single-rail supply is better because of the flexibility it provides.

 

[John]

Originally posted by: TransientBen
You can go wrong with a quality unit of any sort. I'm not sure if you'll be able to get a 24-Pin PSU -without- dual rails, so may as well invest in a decent one.

All of the following have a single +12v rail and a 24-pin power plug instead of a 20 to 24-pin adapter.

Enermax 460w

Tagan 480w

Forton Blue Storm 500w

OCZ PowerStream 520w (I own this one)

There are several more as well.

 

[jose]

See sig. Antec 550EPS $120, zero problems..

Regards,
Jose

 

[slash196]

Originally posted by: John

Originally posted by: TransientBen
You can go wrong with a quality unit of any sort. I'm not sure if you'll be able to get a 24-Pin PSU -without- dual rails, so may as well invest in a decent one.

All of the following have a single +12v rail and a 24-pin power plug instead of a 20 to 24-pin adapter.

Enermax 460w

Tagan 480w

Forton Blue Storm 500w

OCZ PowerStream 520w (I own this one)

There are several more as well.

That Blue Storm has dual rails.

 

[John]

Nice catch.....I guess that's what I get for copy/pasting from a previous thread.

 

[ssvegeta1010]

Also you can get a 36A single rail Sparkle 550W for 109 shipped

Here: http://www.newegg.com/app/ViewProductDesc.asp?description=17-103-478&depa=0

 

[Algere]

Is it true that dual rail psus are not worth buying?

Depends...

If you're overclocking & under heavy load, dual rail PSUs are more stable than a comparable single rail PSU but at the same time you probably* won't get as many usable amps due to the seperation of one big rail into two smaller ones. It's somewhat like comparing a dual core CPU (3 GHz per core) against a 6 GHz single core CPU, if performance scales linearly with frequency & all else is ignored e.g. cache size, memory speed, etc.

*In some situations a two rail PSU's total amp output can fully be utilized. Total amps are usable therefore it becomes equal to a comparable single rail PSU's output.

DFI Ultra-D
AMD a64 winchester 3200+
OCZ 3200 Plat rev2 2x512
BFG 6800 GT OC
2 IDE hdd's
2 Optical Drives
Audigy,
Fans, etc.

*I'm going to overclock, planning to get 2,6-2,7 ghz.

By your specs & intentions, I'd go for that dual railed Enermax. It's +12V two rail design** is the best (unless someone can prove different) I've seen to date for a dual rail PSU.

**By that I don't mean most power outputted. If based on most power output for a dual rail PSU, OCZ's 600W Powerstream gets my vote.

Update: Found out the Ultra-D is a dual video card capable MB - wasn't apparent to me before. I'm guessing you intend to go that route in the future. If so, you may wanna go with a single rail PSU like the one ssvegeta1010 suggested to anticipate increased power needs of future graphics cards albeit sacrificing dual rail benefits. If not, for your listed specs the Enermax is still a viable option that exceeds nVidia's requirement for SLI'd 6800 GTs let alone single video card systems.

Enermax 495AX Dual rail (12v1@18A, 12v2@16A according to newegg, 18A according to official website)

32A balanced between two rails with a 18A limit per rail.

 

[ribbon13]

I second the sparkle. Notice the last reviewer!

It powers a Rockford Fosgate 500W Class D mono sub amp. Which fried an X-Connect instantly! hahaha!

 

[jose]

Does the Sparkle have 2 fans ? It looks very nice for the price..

Just checked the specs on the Sparkle vs the Antec EPS versions.

Sparkle --------- Antec
+3.3V 27A --------- 32A
+5V 29A --------- 40A
+12V 36A --------- 36A
-12V 0.8A --------- 1A
+5VSB 2A -------- 2A


Regards,
Jose

 

[Zepper]

Dual +12 is an artifact of the recent ATX standards change which was a reaction to the ever higher demands on the +12 rail. It was done more for safety than any other significant reason. Single rail is more flexible but having that kind of Amperage available on a single +12 rail can be lethal under some circumstances. So be careful out there!
. Just about everything in the PC that uses +12 actually regulates and filters it down to a different voltage locally. So minor fluctuations in the +12 will have little effect of these devices. I'll go for single-rail every time.

.bh.