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Can I use a separate PSU for RTX 3090?

TizToz
By TizToz
in Power Supplies
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Posted

Hello,

I have bought EVGA RTX 3090 and it needs 750 watt PSU, and my current PSU is only 550 watt.

I have bought a 1000 watt PSU, and I will install it later when I have the time.

 

My question: 

can I leave all my working PC as it is (for now) with its 550 watt, and plug the 3090 in the PCI express slot, and give it 3x8pin power from the 1000 watt PSU that is not installed yet in the pc? Meaning I will have 550 watt psu for all the pc except the 3090, and the 3090 will take its power from a completely separate PSU.

 

If yes, is there any thing I should do before I connect it?

 

 

Thanks 

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Posted

You'd need a way to power them on at the same time.

Just installing the 1000-watt unit would be best.

elephants

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Posted

So long they support the power requirement, it shouldn't matter were it comes from and so long the cables are correct and a good unit.

Else like above, everything needs to be on before turning on your computer though. Most likely not the best way to do stuff, don't think it will cause any harm tho.

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Posted

Yes, you can.

 

Beware. Do it at your own risk.

 

Just jumper the green cable (PS_ON) and one of the ground cable (COM) on the main power ATX connector using some kind of short wire. Power on/plug in the PSU and it'll turn on. To turn off it, just unplug/switch off the PSU.

 

Although I rather to change the PSU right out when it's there, make things simpler.

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How to Turn on a Computer Power Supply Without a Computer - Instructables

 

image.jpeg.1431d388cb42e8c673f0949cffcc8e5f.jpeg

 

How To Safely Turn On A Power Supply Without A Motherboard | Daily Grind

 

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Posted
  • Author

Thank you all for the replies. As have been said here, I will make things more simple, and install the new PSU as soon as I can. 

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Posted

As others have said you should just install the new PSU. It would be far simpler than trying to run dual power supplies. That does work if needed, though. 

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Posted
10 hours ago, TizToz said:

I have bought a 1000 watt PSU, and I will install it later when I have the time.

Just take the time to install the new power supply. It's not going to take that long to swap PSUs and cables over. Make sure you don't re-use the cables from the old power supply on the new one (if they're modular cables)

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  • 5 months later...
Posted

I'm going to do it. I have 2 ROG Thor 850's and (individually) they aren't enough for the 3090 xtreme ... Too much draw, system reboots (the display shows over 865 sometimes, kinda impressive) so I'm jumping the second to use just for the GPU. Also will be able to read out the cards usage in real time... The power on pin just needs a comm pin ... There's nothing with load being messed with so I think everything should be fine.

I'll report back...  If I remember 

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Posted

two separate psus.. sounds concerning and inefficient... cheaper to buy one good one...

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Posted
50 minutes ago, marksaidso said:

I have 2 ROG Thor 850's and (individually) they aren't enough for the 3090 xtreme

That's because Seasonic PSUs have issues with Ampere, not because a single decent 850W PSU isn't enough.

:)

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Posted

This thread is six months old.

 

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