modern systems: 5v/3.3v rails

[Soulkeeper]

Since 12v supply has become the dominating issue over time I'm wondering how many amps are actually used on the 5v/3.3v rails in a modern system ?

ie with a system like the following:

socket AM3+ or 1155
1 or 2 modern vid cards (ie: 7870)
4 hard drives

Is the requirement on 5v/3.3v something so small it's silly now (ie: 20W)?
any links of people measuring for a modern system would be great.

thanks

 

[contrvlr]

Since 12v supply has become the dominating issue over time I'm wondering how many amps are actually used on the 5v/3.3v rails in a modern system ?

ie with a system like the following:

socket AM3+ or 1155
1 or 2 modern vid cards (ie: 7870)
4 hard drives

Is the requirement on 5v/3.3v something so small it's silly now (ie: 20W)?
any links of people measuring for a modern system would be great.

thanks

Been a couple of years, but I had a fancy psu that showed between 50 and 60 watts combined on the minor rails ( I7-930 @ 3.8 / 3 x 2 DDR3 @ 1.65v / GTX460TOP / 1 HD / 1 OD / MCP355 and 6 fans)
The 3.3v used the greater portion of that

 

[Soulkeeper]

that seems reasonable

my 400W seasonic gold only supplies 100W on the 5/3.3
where my old pile of antec psu's easily put out 2-3x that but have only about 200W on the 12v

I'm just thinking all these old psu's (400, 430, 480, 550) are worthless now :/
They are basically sub 85% eff 200W psu's by today's standards

 

[nightspydk]

If you got a psu that allocate 60 W for the 3,3/5V rails this day and age it is because that PSU is powerful to begin with. Those rails are more or less insignificant in a modern PSU. We are talking about old ISA days and they are long gone.

Yep the 12V rail is where you draw you power on all important components 2013.

Oh sorry mate to your question. You cannot transfer electricity from one rail to another unless you hack the unit or something. Not to be a smartass, but the 3,3V rail is gone and the 5V rails going, so that's a no go..

In essense a PSU is just a a bunch of transformers..

 

[Soulkeeper]

If you got a psu that allocate 60 W for the 3,3/5V rails this day and age it is because that PSU is powerful to begin with. Those rails are more or less insignificant in a modern PSU. We are talking about old ISA days and they are long gone.

Yep the 12V rail is where you draw you power on all important components 2013.

Oh sorry mate to your question. You cannot transfer electricity from one rail to another unless you hack the unit or something. Not to be a smartass, but the 3,3V rail is gone and the 5V rails going, so that's a no go..

In essense a PSU is just a a bunch of transformers..

Yes, I was just trying to quantify where we stand today.

Google wasn't turning up any bench tests for 3.3/5.0 needs on current systems.
I guess "enough" is a few dozen watts ...

thanks

 

[nightspydk]

It's not that long ago I tried get a decent roadmap of a 2013 mobo in this context and if you do, you can determine where all the juice goes. My initial post stands though, but you could need a bit of elaboration I know.