12V1 of 15A + 12V2 of 14A = 12V 29A?

[Alzes]

Hey guys,
I've always read posts in this forum but just created a user today...

Anyway, I wanted to ask...
Some power supplies have two +12V rails (do they call them rails? lol), so if a power supply has 12V1 with 14A and 12V2 with 15A, does it count like 29A?

Can I hold a 8800GT and an E4500 with such a supplier? (solid FSP supplier of 400W).

Thank you.

 

[MarcVenice]

no not exactly, although it will often be very close, and sometimes you can in fact add them up, because they say it's 2 12v rails, but it's just one rail in reality. 400w FSP psu might cut it for a e4500 and 8800gt, but it will be close. Rather get a 500w antec earthwatts or corsair 450vx.

 

[Harvey]

Originally posted by: Alzes
Some power supplies have two +12V rails (do they call them rails? lol),...

Voltage supply lines are called rails, but they don't necessarily laugh about them.

... so if a power supply has 12V1 with 14A and 12V2 with 15A, does it count like 29A?

The answer is a qualified "yes." Your PSU is spec'd with two separate 12 volt rails. One can supply circuits requiring a total of 14A, and the other can supply a total of 15A. That's a total of 29A, but neither line can supply more than its rated load. That means you should make sure that you arrange the connections to various components so that the total current demand on either line doesn't exceed the rating for that line (14 or 15A).

Hope that helps.

 

[Alzes]

Thanks guys for the quick replies.
I would love to get a different PSU but sadly it's the only one that gets into my budget that has enough voltage on the 12V. (the other choice is HEC 450TDT 450W but it doesn't have enough voltage on the single 12V.)

I'm glad to hear that the FSP will cut it, and Harvey as for your remark on arranging the connections... I'm guessing the store I'm buying it from knows it? because I have no idea what you just said (YEP... a noob).

And another question... Will I be able to do a OC to my E4500 with that PSU and 8800GT? or is it too much to ask?

 

[JEDIYoda]

Originally posted by: Alzes
Thanks guys for the quick replies.
I would love to get a different PSU but sadly it's the only one that gets into my budget that has enough voltage on the 12V. (the other choice is HEC 450TDT 450W but it doesn't have enough voltage on the single 12V.)

I'm glad to hear that the FSP will cut it, and Harvey as for your remark on arranging the connections... I'm guessing the store I'm buying it from knows it? because I have no idea what you just said (YEP... a noob).

And another question... Will I be able to do a OC to my E4500 with that PSU and 8800GT? or is it too much to ask?

My friend-- FSP does not make a bad line of PSU`s.
The issues with FSP is that under real heavy loads the go out of spec.

Have fun with your PSU!!

 

[Alzes]

Originally posted by: JEDIYoda

Originally posted by: Alzes
Thanks guys for the quick replies.
I would love to get a different PSU but sadly it's the only one that gets into my budget that has enough voltage on the 12V. (the other choice is HEC 450TDT 450W but it doesn't have enough voltage on the single 12V.)

I'm glad to hear that the FSP will cut it, and Harvey as for your remark on arranging the connections... I'm guessing the store I'm buying it from knows it? because I have no idea what you just said (YEP... a noob).

And another question... Will I be able to do a OC to my E4500 with that PSU and 8800GT? or is it too much to ask?

My friend-- FSP does not make a bad line of PSU`s.
The issues with FSP is that under real heavy loads the go out of spec.

Have fun with your PSU!!

Are you being serious or sarcastic?

BTW the PSU I'm talking about is this one:
http://www.fsp-power.ru/englis...nid=1&fid=52&proid=206

 

[Alzes]

Originally posted by: Alzes

Originally posted by: JEDIYoda

Originally posted by: Alzes
Thanks guys for the quick replies.
I would love to get a different PSU but sadly it's the only one that gets into my budget that has enough voltage on the 12V. (the other choice is HEC 450TDT 450W but it doesn't have enough voltage on the single 12V.)

I'm glad to hear that the FSP will cut it, and Harvey as for your remark on arranging the connections... I'm guessing the store I'm buying it from knows it? because I have no idea what you just said (YEP... a noob).

And another question... Will I be able to do a OC to my E4500 with that PSU and 8800GT? or is it too much to ask?

My friend-- FSP does not make a bad line of PSU`s.
The issues with FSP is that under real heavy loads the go out of spec.

Have fun with your PSU!!

Are you being serious or sarcastic?

BTW the PSU I'm talking about is this one:
http://www.fsp-power.ru/englis...nid=1&fid=52&proid=206

I'd like more comments, it's very important to me.
Thanks.

 

[jonnyGURU]

Originally posted by: Harvey

The answer is a qualified "yes." Your PSU is spec'd with two separate 12 volt rails. One can supply circuits requiring a total of 14A, and the other can supply a total of 15A. That's a total of 29A, but neither line can supply more than its rated load.

That is incorrect. Rails are not additive. Each rail, added to the next often exceeds the actual output capability.

This is because, as Marc suggested, they take the +12V rail, split it into two circuits and just put a "limit" on each circuit that prevents no more than a specified amount of current to be delivered to a connector.

To find out how much +12V your power supply really has, you need to find a wattage number under neath the two +12V rails or some verbiage that says something like "combined +12V shall not exceed...."

Take this FSP for example:

http://images10.newegg.com/New...mage/17-104-952-03.jpg

It says +12V1 is 18A and +12V2 is 18A. That's 36A, or 432W! 432W? That's greater than the actual capability of the PSU!! If we look down at the last line, it says the +12V1 and +12V2 is 348W.

What that means is, you can put 18A on one rail, or 18A on the other, but not 18A on both. If you put 18A on one rail, that only leaves 11A available to the other because the maximum +12V output is 348W.

For your FSP to have only 14A and 15A means it's pretty old. The FSP 400W units I could find all had more. I wouldn't suggest it for your build, but if you already have it, you might as well try it. And if the computer keeps shutting down or locking up, suspect the PSU first.

 

[Alzes]

Originally posted by: jonnyGURU

Originally posted by: Harvey

The answer is a qualified "yes." Your PSU is spec'd with two separate 12 volt rails. One can supply circuits requiring a total of 14A, and the other can supply a total of 15A. That's a total of 29A, but neither line can supply more than its rated load.

That is incorrect. Rails are not additive. Each rail, added to the next often exceeds the actual output capability.

This is because, as Marc suggested, they take the +12V rail, split it into two circuits and just put a "limit" on each circuit that prevents no more than a specified amount of current to be delivered to a connector.

To find out how much +12V your power supply really has, you need to find a wattage number under neath the two +12V rails or some verbiage that says something like "combined +12V shall not exceed...."

Take this FSP for example:

http://images10.newegg.com/New...mage/17-104-952-03.jpg

It says +12V1 is 18A and +12V2 is 18A. That's 36A, or 432W! 432W? That's greater than the actual capability of the PSU!! If we look down at the last line, it says the +12V1 and +12V2 is 348W.

What that means is, you can put 18A on one rail, or 18A on the other, but not 18A on both. If you put 18A on one rail, that only leaves 11A available to the other because the maximum +12V output is 348W.

For your FSP to have only 14A and 15A means it's pretty old. The FSP 400W units I could find all had more. I wouldn't suggest it for your build, but if you already have it, you might as well try it. And if the computer keeps shutting down or locking up, suspect the PSU first.

I don't have it yet... but it's the only one that fitted into my budget.
I have a friend who has a HEC 6A19 case with a 400W PSU that came with it (built in), and he runs a 8800GTS 640MB + E6300 system with it.

How is this PSU
http://www.hecgroupusa.com/product/83

 

[jonnyGURU]

Originally posted by: Alzes

I don't have it yet... but it's the only one that fitted into my budget.

Why don't you tell us "your budget" and where you're located and then maybe we can help you find something better for your money.

 

[magreen]

5 cups of water + 2 cups of sugar != 7 cups of sugar water

 

[Zap]

Haha, good one magreen.