I don't really think that it's the card's performance. It happened with the latest patch and is also only happening in DX11 mode. DX9 mode, which has worse performance, doesn't crash. And it also happens only in Final Fantasy, no other games have any issues.
Must be a specific problem between the newest driver and the patch.
I hope that it'll be fixed soon, DX9 Mode has some ugly fps drops in places.