what are the games that need the most gpu power? (available on gog)

my brother gifted me a new graphics card and now he wants to see what it can do.

have a nice day. :)

Metro Exodus, (incoming) Control or any game that has RTX features really and especially if you turn up the settings.

Kingdom Come Deliverance i guess can be fairly demanding with HD texture pack and maximized settings despite not having RTX.

From my perspective, The Witcher 3 is still the first game that comes to mind, even though there might be several games by now that surpass its system requirements (it's 5 years old already, after all, but still one of the biggest AA-A? games on here, I think).

If we're talking about games available for purchase right now, it's probably Metro Exodus that'll stress your GPU the most, as mentioned above.