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AndyOCZ

A64 NF4 and NF3 Power Supply Requirements: Amps and Split Rails

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Let's start from the top. There are many reasons for the changes in the ATX Power Supply specification but here are the big ones.

 

ATX 12V 2.X provides a 2x12 (24pin) ATX connector, a 2x2 CPU connector, 4pin molex, 4pin floppy, SATA power and 2x3(6pin) PCIe connector specification.

 

The 4pin CPU power connector is on its own 12V rail. The reason for the split 12V rails is to provide an independently regulated 12V power supply to the CPUs PWMIC circuit.

 

The other 12V rail provides power to the other connectors that require it.

 

The change from the 2x10 to 2x12 ATX connector is to provide more current to the motherboard to support the PCIe requirements for display adapters. Additionally as more components are added to the mother board current leaks and voltage drops are inevitable.

 

DFI, as well as other manufacturers, has added additional power connections on the motherboard. This allows for a much more stable supply of power to the critical areas of the circuits involved. This is why under certain conditions you might be able to run an nF4 board without the additional 4pin molex and floppy connector attached. The end result is current is delivered exactly where it is needed without affecting other components even if they are on a common circuit path.

 

As far as power supply regulation of the 12V output. The ATX 12V 2.x spec calls for the rails to be independently regulated. This means one rail can have varying loads without effecting output of the other.

 

I hope you find this helpful. If you have further questions, just post back!

 

ExRoadie

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Let's start from the top. There are many reasons for the changes in the ATX Power Supply specification but here are the big ones.

 

ATX 12V 2.X provides a 2x12 (24pin) ATX connector, a 2x2 CPU connector, 4pin molex, 4pin floppy, SATA power and 2x3(6pin) PCIe connector specification.

 

The 4pin CPU power connector is on its own 12V rail. The reason for the split 12V rails is to provide an independently regulated 12V power supply to the CPUs PWMIC circuit.

 

The other 12V rail provides power to the other connectors that require it.

 

The change from the 2x10 to 2x12 ATX connector is to provide more current to the motherboard to support the PCIe requirements for display adapters. Additionally as more components are added to the mother board current leaks and voltage drops are inevitable.

 

DFI, as well as other manufacturers, has added additional power connections on the motherboard. This allows for a much more stable supply of power to the critical areas of the circuits involved. This is why under certain conditions you might be able to run an nF4 board without the additional 4pin molex and floppy connector attached. The end result is current is delivered exactly where it is needed without affecting other components even if they are on a common circuit path.

 

As far as power supply regulation of the 12V output. The ATX 12V 2.x spec calls for the rails to be independently regulated. This means one rail can have varying loads without effecting output of the other.

 

I hope you find this helpful. If you have further questions, just post back!

 

ExRoadie

 

 

Thanks for taking the time to explain in detail the different reasons behind the various powers and power connections. That answers all my questions and then some.

 

Ray

:D

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Guest RedRider

Up and running last few days and notice that Smart Guardian shows the +12v at 11.96v at idle (have not worked out how to test at load) Have not had much to do with the power supplies so is 11.96 the norm or should it be more. Next setting up on the OCZ 520 runs at +12.28/35v.

What would be best volts to run at with the extra gear I have (SLI, 6 fans, 6 hardrives).

Thanks

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Up and running last few days and notice that Smart Guardian shows the +12v at 11.96v at idle (have not worked out how to test at load) Have not had much to do with the power supplies so is 11.96 the norm or should it be more. Next setting up on the OCZ 520 runs at +12.28/35v.

What would be best volts to run at with the extra gear I have (SLI, 6 fans, 6 hardrives).

Thanks

Your 12V rail at 11.96V is real good. Not sure what you mean by "best volts to run at". You should strive to get as close to 12V as possible.

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So my understanding of the split rails is, that if you have a power supply that actually has independant 12V converters (separately regulated - voltage) then the motherboard would have to also support this... right? Is this reasoning correct? Separate regulation of the voltage would not guarentee current sharing between the two converters... therefore you would need to separate the two power rails on the motherboard as well?

 

If so, then which connectors are on which 12V power rail?

 

Should I just take my DMM to the motherboard or is there a record of this split? Am I barking up the wrong tree?

 

Well your dog did a bit more than bark up the tree. He actually chased the cat up the sucker

and got his @ss stuck at the top lol.

 

Viper

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Up and running last few days and notice that Smart Guardian shows the +12v at 11.96v at idle (have not worked out how to test at load) Have not had much to do with the power supplies so is 11.96 the norm or should it be more. Next setting up on the OCZ 520 runs at +12.28/35v.

What would be best volts to run at with the extra gear I have (SLI, 6 fans, 6 hardrives).

Thanks

 

Do not go by what on board sensors are reading. They are notoriously inaccurate and with high

variability from one MB to another.

 

If you want to know want your PS voltages are use a DVM.

 

Viper

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Hope this helps someone. I got all my components yesterday and found a problem,.........the 24 pin and 4 pin connectors on the motherboard are so close together that the oversize Ultra xConnect cable ends won't plug into them; just one or the other. So,........went to NewEgg about 1030 last night and ordered OCZ Modstream with overnight shipping. Hopefully I'll be back in business tomorrow. Thanx to everyone in this forum for all the help so far.

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Hope this helps someone. I got all my components yesterday and found a problem,.........the 24 pin and 4 pin connectors on the motherboard are so close together that the oversize Ultra xConnect cable ends won't plug into them; just one or the other. So,........went to NewEgg about 1030 last night and ordered OCZ Modstream with overnight shipping. Hopefully I'll be back in business tomorrow. Thanx to everyone in this forum for all the help so far.

 

Pretty bonehead move on the part of the designer of that PS lol!!!

 

Viper

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Yeah, although it wouldn't have hurt for DFI to have moved the connectors a little farther apart. Man, they are close! Oh well, my son inherited the ultra.

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