Temperature: Influenced by things like, chassis airflow, ambient temperatures, and power limit(higher power limit = harder to cool and thus require beefier cooling solutions to match, and that's not taking into account fan curves).
ON PAPER, the
Strix would be the hotter card compared to the
Suprim X...
Memory temperature: Just like the first one, you could be waiting AGES for a concrete response on this one too, because it requires someone who's bothered to test them both.
Also influenced by card power draw; Vram uses very little power, but it soaks up some of the heat radiating off the PCB and GDDR6X has high operating temperatures.
Performance: A tie; not enough to matter while you're in the middle of various actions in game.
TL;DR: The cheaper of the 2.
Same price? Then the one that is more aesthetically pleasing(to you).
Another one would be the company that has the better customer service reputation in your area; you may be less likely to get bent over if something goes south.