Can I cascade computer 2 PSUs to provide extra wattage?

[JohnJohn20]

Hi. I just put a PCI Express graphics card in my computer and now the computer won't even start, just makes a buzzing sound.

I am told this is due to the existing 400 watt PSU is too small. Rather than fork out for a high wattage PSU, can I get another similar PSU and either:
1. Connect the 4-pin Peripheral power connector feeds (yellow 12V, red 5 V and two black grounds) together in a parallel fashion, and use this to power the computer.
2. Just run the PCI Express graphics card (which is powered by a seperate 6-pin connector rather than through the mainboard connector) off the new PSU while the rest of the computer is powered off the original PSU.

In this case, would it be advisable to connect the ground wires (the two black wires) of the two PSUs 4-pin Peripheral power connector feeds together to keep the 0V feeds the same?

Thanks.

 

[mister_rf]

2. Just run the PCI Express graphics card (which is powered by a seperate 6-pin connector rather than through the mainboard connector) off the new PSU while the rest of the computer is powered off the original PSU.

The two ground wires are connected on the PCI graphic card connector. No need for additional connections.

In this case you will need a special adapter, e.g.

 

[tpetar]

Apsolutely not for both questions. If you try that maybe your next step will be search ebay for new motherboard.

I saw earlier some manufacturers of power supply offered cascade link of two or three power supply, this power supply have some electronic control of voltages and other things inside. With ordinary power supply this is very dangerous to do.

 

[mister_rf]

I think there's been a misunderstanding. There’s no cascaded power supplies, just a separate power supply for the video card. It’s better to use some dedicated 12V power supply.

 

[tpetar]

Paralleling power supply is bad idea, also separate power supply for video card is also bad idea.

Should be one with enough power to support all needs of system parts.

 

[mister_rf]

No suggestions were made for paralleling power supplies. Just using a separate power supply for the video card, and that’s a normal situation used in many electronic devices.

User need to choose what’s the best decision to take comparing the price/work involved for this action, between changing the actual power supply and adding a second 12V video card power supply.

 

[sky_123]

Agree, you can use a separate supply for the video card, it is designed for this, and the connector as suggested by mister_rf doesn't parallel them, so
it should work.
Most chassis however only have space for one PSU : ) Might be easier to change PSU as you say.

 

[tpetar]

This power connector on video cards are connector to make direct power from PSU to Video, to avoid high currents over motherboard. He should buy one PSU enough to support all parts. Today there is 650W, 750W, 1KW, 2KW, I even saw 2,7KW.

This second PSU can kill motherboard like rabbit. Of course I'm always open for experimenting, lets see whats will happen when he try, why not. ;-)

I have custody for 18 big servers half of them have two PSU inside each big case, but second PSU is only for farm of hard disks inside.

 

[mister_rf]

So, there’s a second power supply inside the server for the HDDs… What’s the difference using the second power supply for the video card?

 

[tpetar]

Best is that Johny make test and if parts survive I pay beer. ;-)

 

[rajudp]

i have not tested using a second power supply, but it should work, connect only the video card 12v supply from one smps make the ground(black wire ) common for both.
new smps need a PS_ON pin short that pin in both smps( green wire ) then it should work, or you can connect a 12v supply for graphics card making the ground common for both

---------- Post added at 21:32 ---------- Previous post was at 21:31 ----------

i have not tested using a second power supply, but it should work, connect only the video card 12v supply from one smps make the ground(black wire ) common for both.
new smps need a PS_ON pin short that pin in both smps( green wire ) then it should work, or you can connect a 12v supply for graphics card making the ground common for both

 

[tpetar]

Lets make test, theory is useless if there is no practical experiment. :smile:

 

[rajudp]

it will work 100% if the only the problem with graphics card load

 

[tpetar]

Johny just receive 100% confirmation from our friend Rajudp, he can proceed with this configuration of PSU.

Of course this is very greatfull also for me, for future use of PC.

 

[JohnJohn20]

Thank you all. I will give it a shot over the weekend.

I will power up another PSU and use the 4-pin Peripheral power connector feeds (yellow 12V, red 5 V and two black grounds) to power the PCI card only.

Doing this I am assuming that the PCI card receives no power via its connection to the motherboard so there shouldn't be any earth loops or similar. Please correct me quickly if I am wrong.

Stay tuned....

 

[rajudp]

if you check with meter may 5v will display at some connections that is normal