Buying a 500w power supply for two GPUs that require 400 watts total sounds as it would work, but I would recommend going with a higher wattage power supply to give yourself more headroom. If you're building with modularity in mind, you'll need to consider the power consumption of any additional components you plan to add. You'll also want to make sure that the power supply you buy has enough PCIe power connectors to support all of your GPUs.
500w power supply is an office power supply, and as a rule there is one 8-pin connector. An 8-pin connector can pass power up to 288 watts, respectively, 2 connectors for 500-600 watts are difficult to use.
And now the market is full of ATX and server blocks at a cheap price.
I have run about 6 Nvidias Gtx 1050 ti without connectors that took power from the motherboard with just a Be Quiet Dark Power 550 watt while I have run 2 x Rx 580 8GB with a Corsair 500 watt PSU,meaning that the best options for the mining rig of 3060 ti-s should be a 1300 Evga power supply which will run them smoothly without burden on the PSU and they make some of the best quality power supplies out there,they to some models go much further offering a 10 year warranty (don't know if they still do this but they used to do this a lot).
This power supply can run up to 8 cards with burden,I mean it will be using about 85-95% of all power and it will constrain the PSU but I know this runs such cards and 8 of these near 500 Mhsh a considerable amount for just a mining rig I would say.
No need to try and find other power supplies as the price difference will be small but the quality leap will be big if you get the wrong one.
6 Nvidias Gtx 1050 ti x 75 watts, that's 450 watts
Also 100 watts for the processor, motherboard and hard drive. Be Quiet PSUs are good and they can work with more load, they have 5-10% in reserve. But agree that this is the wrong configuration for the mining farm. Cooling problem and your transistors will explode. I already had a bad experience.
