Questions about RTX 6000 Ada

Nothing in theory, but there are small differences in performance and the PNY is not quite as powerful as the actual manufacturer. However, the cards do not differ in terms of connections and compatibility.
Here is another larger report on the differences between brands of graphics cards:
https://www.computerbild.de/artikel/cb-Tipps-PC-Hardware-Grafikkarte-kaufen-Hersteller-Unterschiede-Beratung-27530601.html