Building rig of One PSU and two Mobo's

Hi all
I have one PSU 1500w and two Mobo's with 3 PCI ports each,
Six GPU and six risers.

My question is,
if it's doable to power the motherboards (with 3+3 GPU) with just one PSU so to have two different rigs.

Has anyone done it?

Most PSU's have only one motherboard power supply. It would probably be difficult to do.

You should buy a second PSU.

Thanks blockops
Indeed it has only one.

If a second (simple) PSU powers up only the 2nd mobo and all the other hardware components (Risers, GPUs) connect to the 1500w.
Is this going to run?

I have never tried this but i don't see why it shouldn't work. How long the motherboard that is connected to the 1500W is on. If not you could always bridge the 24pin connector.

I have a 1300W PSU that i'd be willing to part with for $135 USD shipped to the US. Will discuss international shipping if you're interested.

I also have 2 RX 470 8GB cards I'd sell with it too. $450 bundled and shipped to the US. Will discuss international.

I wouldn't recommend this. The floating ground between the two PSUs could cause an unexpected voltage difference between the motherboard and the rest of the components. You could get around this by connecting a ground from the motherboard to a ground from another component, but that's just putting a band-aid on a bad idea.

Yes this should work fine. I am using 2 PSUs for one MB but what your describe is very similar. You will just need to connect the 24 pin and 4x2 CPU connector from the 2nd PDU whereas in my case they go unused.