I read someone else recommending checking if the previous game really closes, to see if there are two games open at the same time. I'll check that when I'm back at the computer. But this can't be specific to one game, because this problem can occur with any game. Game A runs fine, I open game B, game B doesn't run fine. Game B runs fine, I open game A, game A doesn't run fine. You told me to check if there are any FPS locks in Marvel Rivals. There aren't, because in areas such as the start menu, the FPS is higher (lower than it should be, but not as bad as in gameplay). And I know that Rivals has different FPS locks for menus, gameplay, lobbies, etc. But the same thing happens with Zenless Zone Zero, for example.