Multiple PSU Rails?

[RyderOCZ]

I have seen several posts from you guys complaining about multiple rails on a PSU. Might I inquire as to why some of you feel that multiple rails is so bad?

Thanks :)

[Absolute_0]

I have been told that multiple rails split the +12v power and so not as much juice cannot be supplied to one area.

I was told specifically that AMD 64 prefers a single large +12v rail rather than smaller split rails.

[tagteam]

Actually multiple rails is not always bad at all, ONLY sometimes the manufacturers wrongly distribute the +12V rails so it won't perform as it should. Some manufacturer's multi rails PSU works ok, but some doesn't, like what we saw in some hi-end brands.

Here's one link: http://www.theinquirer.net/?article=29940

[RyderOCZ]

Bump? Anyone else?

[uOpt]

Need to power a Supermicro H8QC8 with 4x 875 and 8+ GB RAM which needs two 8-pin EPS12V, plus the 24 pin.

I had a custom build of the PCP&C 1 KW (with two native 8-pin) which failed to power up this unit. After several phone conversations and loading 5V to rule out cross-loading problems they concluded that I overload one of the rails in the unit (it has 1x 36 A and 2x 16 A).

The 520 W powerstream worked just fine, BTW :)

So that is why I concluded I want as few rails as possible. Right now I use a Zippy 700W (single rail). Every day I receive movie studio offers to record the sounds for movies playing on aircraft carrier flight decks in my machine room, so I really want something less noisy, preferrably without doing my own cooling.

The way that the new OCZ and Mushkin PSUs have their 4 rails distributed I cannot make use of the 4 rails anyway. Even if I make my own 6-pin PCIe to 8-pin converters there is just no place to fit the 4th rail, unless I am brave enough to stuff two rails into one 8-pin EPS12V.

I consider ordering the new OCZ 700W and RMAing it with restocking fee in case it doesn't work. But I already did that with the Athena 850W and I don't want to stress my relationship with newegg.

700W, distributed evenly over all rails would be enough for the above rig, BTW. With the Zippy it pulls 368 Watts out of the AC, so there would be plenty room for drives etc.

[RyderOCZ]

The OCZ GameXtream rails are like this:

12V1 - CPU 1
12V2 - CPU 2, PCIe 2
12V3 - Motherboard, SATA, 4-pin molex
12V4 - PCIe 1

So you do have 2 rails in 1 8pin connector (Add CPU1 and CPU2 to make an 8pin)

You could make just 1 of 6pin to 8pin adapters and then use all 4 rails :)

[uOpt]

Hmmm. So CPU1 and CPU2 are the two halfs of the 4+4 EPS12V?

That would indeed give me two rails into one EPS12V 8-pin without myself having to do it, and hence access to all 4 rails total.

Time to order some molex tools I guess. OCZ doesn't happen to make custom builds, do they? :D

[RyderOCZ]

No custom builds...sorry.

Yes the 2 included 4pin connectors (CPU1 and CPU2) go together to form 1 EPS 12V.

Removing any connectors would void the warranty remember...hopefully you can find a female 6pin so you just have to plug in the PCI-e1 into it.

Don't use PCI-e2 because as you see it is connected to the same rail as CPU2

[eva2000]

multi rails aren't bad if say 3x +12v rails @38amps each = 114amps LOL

[RyderOCZ]

multi rails aren't bad if say 3x +12v rails @38amps each = 114amps LOLWith 1% regulation @ full load, 92% efficiency, 1250W continuous output, $195.00 price tag and a partridge in a pear tree.

:ROTF:

[uOpt]

Regulation is for whimps anyway :D

I think I'll give this a shot now.

ETA: PSU, Molexes, crimping tool, wire and a dead chicken for waving ordered. We'll see how this goes.

[LikwidKool]

I just received the GX. Now I don't have a power draw even close to yours, but it is a damn nice PSU.

[nn_step]

Provided that you have 4 strong rails it shouldn't be remotely a problem..
there is only a problem with multible rails if and only if one gets overloaded.
if you can dedicate one rail for the Mobo and one for each graphics card.. there is absolutely no problems.. now you might be wondering why I am saying 4 rails intead of 3. the reason is even if the rail is weak it would be better to seperate the hard/CD/DVD Drives from the Mobo and the Graphics cards.. so they can would in their Peak performance zones. 22A on each rail should be more than enough for now. And just a single idea for you keep dedicated rails for the Mobo and the Graphics but make everything else modular.. in order to help keep the entire set up clean. :up:

[raju]

I would agree with nn_step, 20a rails on multi rails psu's is safe when running dual gpu setups etc. I would have preferred it if my Tagan had modular fittings for sata and molex only, that would help keep the case tidy.

[Sentential]

I have seen several posts from you guys complaining about multiple rails on a PSU. Might I inquire as to why some of you feel that multiple rails is so bad?

Thanks :)

Ive expressed this to the guys at mushkin and Ill pass along what I said to them here. After looking at the Topower spec sheet I think ive grown to dislike multi-rail more than I origionally had previously.

From what the docs Topower showed me Multi-Rail PSUs are *at best* 60% efficient from all combinded rails. Thats really what I have a problem with to be honest.

Most people do not know this since the PSU companies dont want the info released (for the obvious reasons) primarly because it is *alot* more money to make a single rail PSU than it is a multi one.

Thats just why I dislike em, its nothing personal its just an efficiency issue to me

[Orangeman]

RyderOCZ-
I thought Intel dropped the requirement for multiple 12V rails last year? Any truth to that?

[crotale]

This will most likely not be a huge problem in the next couple of months, but when me and Kinc did some heavy overclocking with a 955XE, an OCZ 600W PSU (split rails?) didn't handle load at all past 6GHz. The OCZ 520W PSU handled it without problems and we actually meassured 720W of power entering the PSU during some tests.

Since the days of Presler are counted, this might not be a problem though.

Personally, I don't like the idea of different voltage sources, unless they are spot on on the voltages, but that could change with the load. Different voltages on different rails could cause problems IMHO.

[WeStSiDePLaYa]

seems kinda pointless to have multiple rails.

as those multiple rails will need the same capacitors for each rails, or cut out a few, and have less line stability, or cheaper caps will be used.

if there is only one rail, those caps can all be dedicated to stabilizing the single rail, and higher quality caps can be used.

[-aDaM^]

I think OCZ made a bad move with there new gamexstream / fsp psu :mad: best psu you ever had was the powerstream 520w (topower). I hate multi rails PSU's usally there regulation isn't as good as single rails. After having my PCP&C and Zippy sinlge rails, never would I get a multi rail psu.

[uOpt]

Zipzoomfly screwed up my order, package with this PSU on the packaging list didn't contain the PSU. Argh.

Is it normal that you cannot reach them by phone?

[Cooper]

RyderOCZ-
I thought Intel dropped the requirement for multiple 12V rails last year? Any truth to that?

It wasn`t Intel who decided to make those.
It`s just cos of *safety precautions* end-users cannot have units with output larger than 20A on 12V lines - just cos of this :cool:

I think OCZ made a bad move with there new gamexstream / fsp psu best psu you ever had was the powerstream 520w (topower). I hate multi rails PSU's usally there regulation isn't as good as single rails. After having my PCP&C and Zippy sinlge rails, never would I get a multi rail psu.

You missing one VERY IMPORTANT thing that multy-rail PSU ahve - the way they divide the rails.
OCZ 600W has two 12V rails which are really two rails.
OCZ 700W has 4 *virtual* 12V rails which are made through "dividers" from ONE very powerfull 12V rail.
That`s it - now you know the secret ;) :D

[uOpt]

OCZ 700W has 4 *virtual* 12V rails which are made through "dividers" from ONE very powerfull 12V rail.
That`s it - now you know the secret ;) :D

This rumor that the FSP epsilon series actually is single-rail and just split for protection purposes has been spread by some crazy Russian reviewer of PSUs and made it's way from one review into folklore.

It is not true, I confirmed that with FSP directly.

It is a true 4-rail design.

[Cooper]

This rumor that the FSP epsilon series actually is single-rail and just split for protection purposes has been spread by some crazy Russian reviewer of PSUs and made it's way from one review into folklore.

It is not true, I confirmed that with FSP directly.

It is a true 4-rail design.

Then why it can handle highly OCed crossfire and PentiumD when 600W OCZ can`t ?
And why it can be fully load through only one 12V rail if it`s true 4 rail design ?

[nn_step]

Then why it can handle highly OCed crossfire and PentiumD when 600W OCZ can`t ?
Notice the difference between Quad rail and Dual.. :rolleyes:

[Orangeman]

Cooper-
From what I understand, Intel made the spec. Yes, safety precautions say not to run more than 20A through any one line, but the probability of pulling more than 20A through a single wire is downright remote. Think of splitting off a single line to the CPU, video cards, and everything else using extensions and splitters. Intel supposedly implemented the split rails to comply with the safety regs, but PS makers have said it wasn't necessary. SPCR has a good article in their forums on this.

[Cooper]

Notice the difference between Quad rail and Dual.. :rolleyes:

Notice the difference with max combined 12V line output wattage on both PSUs

OCZ 700W - 700W
OCZ 600W - 240W and 216W

Doesn`t that show anything ? :cool:

[uOpt]

Then why it can handle highly OCed crossfire and PentiumD when 600W OCZ can`t ?


Because it puts two rails on one 4-pin EPS12V (which also means the 8-pin EPS12V since it is a 4+4 connector).


And why it can be fully load through only one 12V rail if it`s true 4 rail design ?

It doesn't according to FSP. Where did you get that info from?

[Cooper]

It doesn't according to FSP. Where did you get that info from?

http://i4memory.com/reviewimages/powersupply/OCZ/gamexstream/html1/photos/GameXstream_032.jpg

http://www.bleedinedge.com/forum/showpost.php?p=170365&postcount=14

I don`t think that presler consumes less than 15A (OCZ`s 18A)

[nn_step]

http://i4memory.com/reviewimages/powersupply/OCZ/gamexstream/html1/photos/GameXstream_032.jpg

http://www.bleedinedge.com/forum/showpost.php?p=170365&postcount=14

I don`t think that presler consumes less than 15A
Dude that is total Watts for the 12v Lines.
Buy one and see how many Amps you can get through it.. because I can tell you right now it is going to be a heck of alot lower than 56A

[uOpt]

http://www.bleedinedge.com/forum/showpost.php?p=170365&postcount=14

I don`t think that presler consumes less than 15A (OCZ`s 18A)

And which part of they put two rails on the EPS12V didn't you understand, precisely?

[uOpt]

Well, I did it.

After a session of first crimping, then soldering, I now have a 6-pin PCIe to 8-pin EPS12V adapter and ...

... the OCZ 700W GXS powers my H8QC8:woot: :woot: :woot: :toast: :toast: :toast: :banana: :banana: :banana:

I remind people that the PCP&C 1 KW failed to do so.

I'll post more later.

[RyderOCZ]

Well, I did it.

After a session of first crimping, then soldering, I now have a 6-pin PCIe to 8-pin EPS12V adapter and ...

... the OCZ 700W GXS powers my H8QC8:woot: :woot: :woot: :toast: :toast: :toast: :banana: :banana: :banana:

I remind people that the PCP&C 1 KW failed to do so.

I'll post more later.Awesome :D

Nice work :)