Choosing a Power Supply Unit

[chershean_chua]

This may help you: Single vs. Multiple +12V rails: The splitting of the +12V rail

Thanks, I think I understand more about the 12V rails, but I still dun understand how the power is distributed across the components of my PC. Sorry if I am slow to understand, but I am very confused right now. Lets say a single 12V rail that produces 40A, but a graphics card takes only 30A through 2 PCI-e connectors, will the 10A left be channeled to other components my means of other connectors like to the processor through the 4 pin ATX?

 

[foothead]

Yes.

But the video card does not use 30A.

Certain plugs are on certain rails so you have to distribute it yourself.
The issue is that your system will shut down if one rail is overdrawn, therefore it could happen with only half of the theoretical power actually being used. Its usually more like 75-85% though because it is hard to do it evenly.

 

[chershean_chua]

Yes.

But the video card does not use 30A.

Certain plugs are on certain rails so you have to distribute it yourself.
The issue is that your system will shut down if one rail is overdrawn, therefore it could happen with only half of the theoretical power actually being used. Its usually more like 75-85% though because it is hard to do it evenly.

What do you mean by plugs? Issit those modular PSUs? What if its not modular?

 

[wol-va-rine]

What do you mean by plugs? Issit those modular PSUs? What if its not modular?

he means the leads from the psu that have the connectors you plug into the motherboard, hard drives, optical drives and video cards, you have to plug those connections into the right slots, the psu doesn't magically power everything within a certain radius by sheer will power alone...

 

[chershean_chua]

he means the leads from the psu that have the connectors you plug into the motherboard, hard drives, optical drives and video cards, you have to plug those connections into the right slots, the psu doesn't magically power everything within a certain radius by sheer will power alone...

How do u ensure that the correct connector is plugged into the correct components? Issit juz plug the SATA power connector to SATA devices, 4 pin ATX to the processor slot, 24 pin ATX to the MOBO power, 6 pin ATX to the GPUs, etc... And the power distribution will be done by the PSU, Amps not used will not blow any system components but just remain redundant? Correct me if I am wrong. Thanks...

 

[foothead]

You have to distribute the power yourself. The PSU will have a list of what is on which rail.

Some power will always go to waste with multi-rails.

 

[chershean_chua]

You have to distribute the power yourself. The PSU will have a list of what is on which rail.

Some power will always go to waste with multi-rails.

Ok... This may sound stupid but where can the list be found? On the PSU itself or on a slip of paper that comes with the PSU? If it is on the PSU, how do you interpret the numbers ther? Thanks...

 

[foothead]

On my gamexstreams it looks like this

note the list at the bottom right corner.

 

[wol-va-rine]

You have to distribute the power yourself. The PSU will have a list of what is on which rail.

Some power will always go to waste with multi-rails.

some of the available power always goes to waste on single rail psus too, no systems use all the available power all the time...

 

[foothead]

True, but more is wasted on multi-rail PSUs.

I also hear there is a higher failure rate.