Safe to connect 2nd PSU to GPU via just PCI-E?

brunor

Prominent
Jan 11, 2018
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I need to troubleshoot my GPU as I cannot overclock the card with a new PSU I have installed, even though it has more power, 650W, compared to the 600W of my old PSU. That's the PSU I want to try powering the card with, but I am unsure of the risks if there are any. I could just replace every connector in my case, but that is quite annoying to do.

I read that you can interconnect two PSUs with a certain connector, but that's not what I want. I just want to connect two PCI-E 6 + 2 cables to my GPU from my old PSU, but since the GPU is also getting power from the motherboard (i.e. from the new PSU) I don't know if that will impact anything.

Specs:

Specs:

Motherboard: Asus Maximus VIII Gene
CPU Cooler: NH D15
CPU: i7 6700K @ 4.2 GHz
GPU: GTX 1080 @ +145 MHz Core Clock, +500 MHz Memory Clock, 120% power limit, 100% core voltage (MSI Afterburner) (this overclock was fully stable in my old system)
New PSU: EVGA G3 650W
Old PSU: Corsair CX600 (used every day since 2013, so nearing it's guaranteed life span)

If anyone knows how to go about doing this I'd appreciate it!
(even if I have no choice but to replace the new PSU with the old PSU entirely)
 
Solution
You have no choice but to replace the PSU. You cannot run two separate power supplies without the (dubious) power supply adapter. The second power supply never gets the signal from the motherboard power switch to ramp up power.

-Wolf sends
You have no choice but to replace the PSU. You cannot run two separate power supplies without the (dubious) power supply adapter. The second power supply never gets the signal from the motherboard power switch to ramp up power.

-Wolf sends
 
Solution