I have an EVGA GeForce RTX 3090 Ti FTW3, which I have been using for two years now. It came with the three-power 8-pin PCIe cable adapter to one 12-pin connecter on the card. The new PSUs have a new norm, ATX 3.0 600W PCIe 5.0, which uses a new cable adapter with only 2 PCIe cables and a 12-volt 600W 12+4 pin plug, the small 4-pins on its top side. I noticed that my 3090 Ti also has this same female format on the card with the 4-pins on top that are not in use. So, I am wondering if I can use this new cable adapter solution to connect my new PSU to my 3090 Ti, it has the 12+4 pin plug, but I don't know if it will supply enough power and it looks a lot more fragile. Can my older card use this solution? What do you all think?

The new power supplies will work fine provided you have enough wattage for that PSU. I have a 1200 watt PSU (which is overkill) with the 12volt 2x6 (12+4) adapter. 

Thanks,  for your fast reply. I have a Corsair RM1200x Shift Series ATX 3.0. I think my RTX 3090 Ti was probably the first EVGA to come with that connecter, I'm not sure. Thanks again.