Heterogeneous GPU driver setup

Hi!

I have one RTX 3090 and one GeForce GTX Titan X GPU and want to use them together. I found both of the GPUs supported by similar driver version, e.g., new feature branch Titan X is supported by 520.56.06 and I am already using 520.61.05 for the RTX 3090. I believe if I install the Titan X with RTX 3090, there will not be any driver issue.

What else do I need to consider for such a heterogeneous setup? What should be an appropriate power supply (PSU)?

Any suggestion would be appreciated.