Second PSU for video card - always ON - problem?

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petreza

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I am adding a video card ( PowerColor RX 480 - 8GB) to a 2U server (don't ask : ) The server PSUs do not have any spare power outputs. They have a 12-wire connection to the motherboard and not the regular 24-wire one.
I plan to get SeaSonic SS-520FL2 520W fanless PSU and power it on with the jumper trick which means it will be always on.

Would this create an electrical problem if the computer is turned off (no power to the card from the pcie slot) while the card still receives power from the power connector on top?

Thanks!
 
Use a relay that closes the circuit when it gets 12v from the server PSU.
 
I've done this before and it didn't create an issue in the short term I used it for. Couldn't say if there would be any long term ramifications though.
 
use a relay that conects the green and ground on the standard psu when 12v is going through the server on. i would only recomend this if you have a good quality psu. could you just tap the 12v of the server psu instead?
 
petreza said:
I am adding a video card ( PowerColor RX 480 - 8GB) to a 2U server (don't ask : ) The server PSUs do not have any spare power outputs. They have a 12-wire connection to the motherboard and not the regular 24-wire one.
I plan to get SeaSonic SS-520FL2 520W fanless PSU and power it on with the jumper trick which means it will be always on.

Would this create an electrical problem if the computer is turned off (no power to the card from the pcie slot) while the card still receives power from the power connector on top?

Thanks!
Click to expand...

I haven't tried this, I won't sway you either way, but one thing pops to my mind - could you measure the voltage potential between the seasonic's 12V versus the server's 12V? Set your multimeter to like 10-20V, stick one lead to one 12V and the other to the second one.
If the difference is significant, like 1V, which is coincidentally GPU-level voltage, I'd be wary.
 
I've got a folding rig with two 970s and two small PSUs running the system. One is a 380W PSU and the other is a 400W PSU. The 380W powers one of the 970s and it's always on. The 400W powers the system and the other 970 and it sometimes powers off due to a power outage. I check on it sometimes and notice the fans (120mm fans are connected to the 380W PSU as well) and the GPU fans are running, but the system is otherwise off. Haven't had any issue with it and it's been this way for over 6 months now.

I really need to go ahead and buy a new PSU capable of powering the whole system.
 
Jorona said:
His PSU doesn't have a 24 pin connector, so that wont work. Vashypooh's link just uses a molex with a relay to click on the second PSU when it gets 12v from the main PSU.
Click to expand...
Both adapters listed (the Add2PSU and Phobya) have 24 pin connectors to the slave PSU. That being said, a 20 pin cable should still plug into both as long as you line them up with the correct side of the plug. Either adapter will work if a 20pin-24pin adapter is used if the OP is the cautious type.
 
I missed that part. Apparently he doesn't have any spare 4-pin molex connectors either so the first adapter wont work either. He'll need to break out the soldering iron if he intends to make this seamless it seems.
 
A 20pin male connector fits in a 24pin female connector just fine. The extra 4 wires are for PCI Express power. As long as the main PSU has a 24pin the slaved PSU can be a 20pin and it should work just fine.
 
It's not a 20 pin ATX connector either. It's a 12-pin. Easily overlooked as I did the same thing.
 
Skillz said:
I missed that part. Apparently he doesn't have any spare 4-pin molex connectors either so the first adapter wont work either. He'll need to break out the soldering iron if he intends to make this seamless it seems.
Click to expand...

If he has anything hooked up with Molex he could just get a splitter. Its not going to adding any load, Its basically just there for sense.
 
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