12V1 14a AND 12V2 13a Amps?
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Add 'em for total amps available to a system or components powered by both 12V rails. Count only one for components powered by one 12V rail*.
*You'll have to find out which 12V rail powers what component(s). May wanna contact PSU maker on that one.
*You'll have to find out which 12V rail powers what component(s). May wanna contact PSU maker on that one.
Not every 2 rail PSU follows that method of power distribution.
No it isn't.
If one 12V rail powers half of a system & the other 12V rail powers the other half, and someone says you need 24A to power up a system -- it's addable (See Operandi's post).
LOL I guess that answer my question. I wanted to know how to find the total amps of the PSU on the 12v rails
Yes, you add the +12 Amps to get the total available. But often you can't really make use of all the Amps due to the way the connections are arranged, without buying or making some realtively unavailable adapters. That's why a single +12 rail is best. Split rails are for wimps!
.bh.
.bh.
Unless your need for cleaner power is more important than higher amp output. I'm sure OC'ers & infrequent upgraders wouldn't mind that.
EDIT: "higher amp output" - meant more usable amps.
You are absolutely right.
All I was trying to say was that if someone needs 16A from one of the rails that can only provide 15A, he is not going to get it even if the other rail can provide another 15A!
Some people are under the impression that the max. output current is automatically adjusted by the PSU, on each rail, to provide any current on each rail as long as it is less than the total. I wanted to say that is not true!
Are there any measurements to show the benefits?
Aren't there individual voltage regulators on the motherboard for VCore, VAGP, VDIMM, ...?
Every component that uses +12V power in a PC does NOT use it directly except for drive motors which are all servo and aren't dependent on the cleanliness or accuracy (within reason) of the voltage to maintain proper speed! All other users have their own on board regulation and filtering thus they don't really care (within reason) what the 12V line is doing.
. The split rail was inserted into the ATX 2.0 spec strictly for safety reasons (high amperage at +12 can be physically dangerous under certain conditions) - go to formfactors.org and read the latest ATX PSU spec bulletin...
. Single rail is more flexible and is the way to go if you really want to be able to readily use all the Amps you paid for. So says Zippy, so say I, so say we all... (tip o' the hat to the new BSG!)
. Unfortunately the split rail (now that it exists) won't die as should be the fate of all ideas that don't pass the technical merit test (which properly weighs ALL factors). Now the big box pushers will feel they have to use them to avoid potential liability.
. Ergo, split rail is for wimps!
.bh.
. The split rail was inserted into the ATX 2.0 spec strictly for safety reasons (high amperage at +12 can be physically dangerous under certain conditions) - go to formfactors.org and read the latest ATX PSU spec bulletin...
. Single rail is more flexible and is the way to go if you really want to be able to readily use all the Amps you paid for. So says Zippy, so say I, so say we all... (tip o' the hat to the new BSG!)
. Unfortunately the split rail (now that it exists) won't die as should be the fate of all ideas that don't pass the technical merit test (which properly weighs ALL factors). Now the big box pushers will feel they have to use them to avoid potential liability.
. Ergo, split rail is for wimps!
.bh.
Just curious if dual rail PSU's arent that good why did OCZ and Enermax choose to make their highest end PSU's dual rail with 20amps on 1 and 18 on the other(OCZ Powerstream 600watt) and 18amps on each rail on the Enermax EG701AX-VE 600watt? Why would they choose to use dual rail? I guess their wimps? LOL 
Originally posted by: ^Sniper^
Just curious if dual rail PSU's arent that good why did OCZ and Enermax choose to make their highest end PSU's dual rail with 20amps on 1 and 18 on the other(OCZ Powerstream 600watt) and 18amps on each rail on the Enermax EG701AX-VE 600watt? Why would they choose to use dual rail? I guess their wimps? LOL
I don't think that they are not good. But, I think that they are not as flexible (as a single-rail). The user will have to be able to load both rails properly. Or else, he/she will be limited by one of the two rails as the bottleneck.
That is a good question to ask the manufacturer. I think one reason can be that it makes the design and manufacturing of the PSU easier.
Just how many amps would a newer non Sli NF4 board use? With a CPU and video card? Provided the video card doesnt get its power from the other rail.
Even o/ced?
Even o/ced?
The point is that splitting the rails to 2 puts a restriction on the system that does not exist in a single-rail system.
You may be fine if your motherboard and graphics card do not need more than what the PSU can provide on one of its rails. But, why buy a 500W power supply if you only need 300W to begin with?
If I buy a 500W power supply, I want to be able to use it all if I needed to. I don't want to be limited by how much current my Motherboard needs and how much current my graphics card needs and ......
understood
but is there a mobo,CPU,video that won't run well on a dual rail aside from maybe a FX system with Sli Ultras? I'll probably never run Sli just for $$$ purposes. I mean when will a system come that will use up that one rail if it isn't here already? I like to try and get at least a couple good years or more out of a power supply if possible. I am just curious so if I buy another PSU I can maybe future proof myself some if possible
There are good power supplies with just one 12V rail.
This is just an example with 28A on the 12V rail.
http://www.newegg.com/app/ViewProductDesc.asp?description=17-101-509&depa=0
This is just an example with 28A on the 12V rail.
http://www.newegg.com/app/ViewProductDesc.asp?description=17-101-509&depa=0
OCZ went with dual rail because it's part of the latest ATX 2.x spec and perhaps beacuse they are concerned with liability - so why not jump on the fadwagon til it fizzles... Thinking outside the box is an uncommon human talent so they'll have plenty o' customers.
.bh.
.bh.
I agree & sorta inferred the same thing (My OP). AFAIK not one single component [today] consumes more than 15A by itself. Therefore as long as dual rail PSUs output power evenly & accordingly based on probable system load, unusable amps due to dual rail configurations should be minimal. A bit more complicated when you get to 3-4 rail PSUs.
Going by what PSU manufacturers, ppl, & reviewers have said about the benefits of multi-rails & no I haven't seen any measurements, nor have I've seen reviewers comment much on what rails power what on multi-rail PSUs (e.g. dual rail vs. 4 rail). However clean power due to multi-rail does sound feasible in that due to the seperation of rails, a noisy component like a CPU affects every other component on the rail it's connected to but not the other & I quote, "The two rails are isolated"
.As for voltage regulation, according to this the voltage regulator is used to lower voltage a PSU outputs so that a CPU can use. Based on that alone, it appears that there isn't any voltage regulation for other components on a motherboard but IIRC DDR & DDR2 has different operating voltages so :roll:. In any case, it's role doesn't look like one that assists in regulating ripples/noise. Now the closest thing I've found relating to voltage regulation & power was on pg. 13 of the ATX 2.2 specs. It says, "Locating the ATX12V power connector near the voltage regulator will help to ensure clean power" (mobo maker suggestions). So while the specs does say the proximity of the power connector to the voltage regulator is dependant for cleaner power, I still don't see any mention of voltage regulators themselves helping regulate ripple/noise. Link if you find otherwise :thumbsup:.
If there's filtering on board, why is it important for PSU makers to list ripple/noise regulation specs? If there's filtering on board why would you need ripple/noise regulation on PSUs & since OC'ing moves your system out of factory specs, is this on board filtering good enough for OC'd systems?
That's one of a few reasons I've heard for the use of multi-rails.
Other reasons or added benefits I've read/heard about multi-rails.
1) Cheaper to make. Would a single rail 700W PSU cost more than a 700W multi-rail PSU???
2) Easier to implement. That or there's the challenge PSU makers would face in attempts to regulate high amperage on a single rail. I suppose reasons 1 & 2 intertwine with one another.
3) Cooler operation, assumingly more important now than ever before. PSUs act as a secondary exhaust for a PC plus add to the fact that the higher the wattage the PSU is outputting, the more heat is produced. Both factor against a PSUs ability to provide full power & as some know, more heat = less power.
4) Prevents CPU power load (and/or other?) from straining the rails. In this case as load increases, voltage goes down. Now my guess is that voltage on the other rail doesn't go down/follow as well.
5) Cleaner power, or at the very least dirty power is isolated to it's own rail.
6) Anything else I might've missed :frown:.
If those reasons are valid. I guess I'm [branded] a wimp
.Under most multi-rail PSUs & scenarios, but not all. Granted, that's in the minority. However once you're into the high wattage range, multi-rail is the only way to go. So shows Zippy's PSU lines (OCZ, PCP&C, etc.), so say I
, so say we all . OT: BTW who/what is BSG?I'm confused
. What is this "technical merit test" & who are these big box pushers? system builders like Dell? PSU makers?!?Think it's safe to say 6-7A for the motherboard or 3-4A or less if it's running @ 8X mode (See max. power consumption for PCIe 16X & 8X; pg. 4). This is of course assuming if you drop down from 16X to 8X & power consumption follows as well. The CPU, I've heard uses between 6-7A & the video card... that's tough. I have no idea how much a video card that receives power from an external source like a 6-pin gfx connector uses. Differs from video card to video card.
Don't know about OC'd conditions.
I presume higher rated PSUs are likely to have lower noise levels at lower power since they're originally rated to work at much higher power (there are exceptions) & then there's that factor of future power requirements [upgrades].
If a FX uses less or equal power to a Xeon & according to nVidia (based on their math/testing) you can run dual 6800 Ultras & a FX off of a dual rail PSU & FWIW/FYI, I assume you're wondering about what to look for in a future PSU. PCP&C's 850W multi-rail PSU is SLI certified by nVidia. The future is multi-rail, just like multi-core is the future for CPUs.
Got a question!
I've heard somewhere that Tagan is going to release a PSU that with a flick of a switch, can run in single or dual rail settings. Is that some rumor (& wishful thinking?) or is there merit to this?
Dual Rail PSUs are still bad news for high end systems. Until they get seperate 12v rails pushing 20A or more each, they're just not practical. Better off going with a single rail PSU with a beefy 12v (30+ Amps).
Originally posted by: Algere
I agree & sorta inferred the same thing (My OP). AFAIK not one single component [today] consumes more than 15A by itself. Therefore as long as dual rail PSUs output power evenly & accordingly based on probable system load, unusable amps due to dual rail configurations should be minimal. A bit more complicated when you get to 3-4 rail PSUs.
Going by what PSU manufacturers, ppl, & reviewers have said about the benefits of multi-rails & no I haven't seen any measurements, nor have I've seen reviewers comment much on what rails power what on multi-rail PSUs (e.g. dual rail vs. 4 rail). However clean power due to multi-rail does sound feasible in that due to the seperation of rails, a noisy component like a CPU affects every other component on the rail it's connected to but not the other & I quote, "The two rails are isolated"
As for voltage regulation, according to this the voltage regulator is used to lower voltage a PSU outputs so that a CPU can use. Based on that alone, it appears that there isn't any voltage regulation for other components on a motherboard but IIRC DDR & DDR2 has different operating voltages so :roll:. In any case, it's role doesn't look like one that assists in regulating ripples/noise. Now the closest thing I've found relating to voltage regulation & power was on pg. 13 of the ATX 2.2 specs. It says, "Locating the ATX12V power connector near the voltage regulator will help to ensure clean power" (mobo maker suggestions). So while the specs does say the proximity of the power connector to the voltage regulator is dependant for cleaner power, I still don't see any mention of voltage regulators themselves helping regulate ripple/noise. Link if you find otherwise :thumbsup:.
If there's filtering on board, why is it important for PSU makers to list ripple/noise regulation specs? If there's filtering on board why would you need ripple/noise regulation on PSUs & since OC'ing moves your system out of factory specs, is this on board filtering good enough for OC'd systems?
That's one of a few reasons I've heard for the use of multi-rails.
Other reasons or added benefits I've read/heard about multi-rails.
1) Cheaper to make. Would a single rail 700W PSU cost more than a 700W multi-rail PSU???
2) Easier to implement. That or there's the challenge PSU makers would face in attempts to regulate high amperage on a single rail. I suppose reasons 1 & 2 intertwine with one another.
3) Cooler operation, assumingly more important now than ever before. PSUs act as a secondary exhaust for a PC plus add to the fact that the higher the wattage the PSU is outputting, the more heat is produced. Both factor against a PSUs ability to provide full power & as some know, more heat = less power.
4) Prevents CPU power load (and/or other?) from straining the rails. In this case as load increases, voltage goes down. Now my guess is that voltage on the other rail doesn't go down/follow as well.
5) Cleaner power, or at the very least dirty power is isolated to it's own rail.
6) Anything else I might've missed :frown:.
If those reasons are valid. I guess I'm [branded] a wimp
Under most multi-rail PSUs & scenarios, but not all. Granted, that's in the minority. However once you're into the high wattage range, multi-rail is the only way to go. So shows Zippy's PSU lines (OCZ, PCP&C, etc.), so say I
I'm confused
Think it's safe to say 6-7A for the motherboard or 3-4A or less if it's running @ 8X mode (See max. power consumption for PCIe 16X & 8X; pg. 4). This is of course assuming if you drop down from 16X to 8X & power consumption follows as well. The CPU, I've heard uses between 6-7A & the video card... that's tough. I have no idea how much a video card that receives power from an external source like a 6-pin gfx connector uses. Differs from video card to video card.
Don't know about OC'd conditions.
I presume higher rated PSUs are likely to have lower noise levels at lower power since they're originally rated to work at much higher power (there are exceptions) & then there's that factor of future power requirements [upgrades].
If a FX uses less or equal power to a Xeon & according to nVidia (based on their math/testing) you can run dual 6800 Ultras & a FX off of a dual rail PSU & FWIW/FYI, I assume you're wondering about what to look for in a future PSU. PCP&C's 850W multi-rail PSU is SLI certified by nVidia. The future is multi-rail, just like multi-core is the future for CPUs.
Got a question!
I've heard somewhere that Tagan is going to release a PSU that with a flick of a switch, can run in single or dual rail settings. Is that some rumor (& wishful thinking?) or is there merit to this?
I don't see why not. Switched circuits aren't exactly rocket science. You have light switches in your house, right?
HardWarrior
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- Jan 26, 2004
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