"Do note that all RTX 40 series will require an ATX 3.0 PSU while all recent Radeon GPUs can use the typical 8-pin power connecter."
Nvidia provides an adaptor with the founders edition cards which supports the existing old standard ATX 2.0 power supply which means that the typical 8-pin cables will work as usual as long as the power supply has the required wattage.
For more info check nvidia website:
(nvidia.custhelp.com/app/answers/detail/a_id/5396/~/geforce-rtx-40-series-%26-power-specifications#:~:text=The%20RTX%2040%20Series%20doesn,the%204080%2012GB%20is%20700W)