Separate PSU for a GPU?

CupONoodles · May 14, 2019

So I’m currently running a salvaged Lenovo Thinkcentre which has a proprietary PSU. I’m hoping to build a system from scratch this summer for Ryzen 3rd gen. However I saw a good deal on a Vega 56 but since the PSU I have had no PCIe power, would it be a problem to run 2 PSUs, the proprietary one for the system, and something like a CXM 550/650W on the GPU? Otherwise the only other option I see would be take a chance on the V56 not being available later in the summer or pulling the trigger on the rest of the system.

tl;dr: is it safe to run 2 PSUs on one system?

BrinkGG · May 14, 2019

7 minutes ago, CupONoodles said:

So I’m currently running a salvaged Lenovo Thinkcentre which has a proprietary PSU. I’m hoping to build a system from scratch this summer for Ryzen 3rd gen. However I saw a good deal on a Vega 56 but since the PSU I have had no PCIe power, would it be a problem to run 2 PSUs, the proprietary one for the system, and something like a CXM 550/650W on the GPU? Otherwise the only other option I see would be take a chance on the V56 not being available later in the summer or pulling the trigger on the rest of the system.

tl;dr: is it safe to run 2 PSUs on one system?

Yes, but you need to turn both of them on at the same time and bridge the GPU power supply.

You can also get/make a connector so both PSUs get their POWER_OK (turn on) signal from the motherboard.

CupONoodles · May 14, 2019

7 minutes ago, Brink2Three said:

Yes, but you need to turn both of them on at the same time and bridge the GPU power supply.

You can also get/make a connector so both PSUs get their POWER_OK (turn on) signal from the motherboard.

So something like this? And just press the power switch for MB and the back of the PSU at the same time?

https://aphnetworks.com/tutorials/psu_paperclip_trick

BrinkGG · May 14, 2019

2 minutes ago, CupONoodles said:

So something like this? And just press the power switch for MB and the back of the PSU at the same time?

https://aphnetworks.com/tutorials/psu_paperclip_trick

Exactly this.

Just make sure you bridge the right pins.

Spotty · May 14, 2019

44 minutes ago, CupONoodles said:

So I’m currently running a salvaged Lenovo Thinkcentre which has a proprietary PSU

As in doesn't have a standard 24pin ATX motherboard connector? You can get adapters that convert the 24pin motherboard connector from a standard ATX PSU in to the proprietary connectors (14pin?). So you would be able to plug a new PSU in to the existing system. No need to run two PSUs at once.
They sell for about $2-$3 on eBay from China. Just make sure whichever you buy is compatible with your motherboard.

50 minutes ago, CupONoodles said:

However I saw a good deal on a Vega 56 but since the PSU I have had no PCIe power, would it be a problem to run 2 PSUs, the proprietary one for the system, and something like a CXM 550/650W on the GPU?

I would probably choose a different PSU if you're planning on running a Vega56. I mean, it'll work... But there's better stuff out there if you're using a high powered GPU.