I have a 850W EVGA G3 and a 750 EVGA G3.

I have a Asrock connected to the 850W along with 3 VEGA 56.

On the 750W PSU I have two VEGA56.

When mining Cryptonight, the 850W psu reads 550W (the Mobo takes about 50-80W) which means the 3 Vega are only drawing about 150-160W.

But on the 750W psu it reads, 410W, which means those are running at 205W!

I can move the cards around between the mobos and the numbers stay exactly the same, so it's not a config or a card issue.

All running on risers. All identical cards. all identical settings.

What on earth would cause this?