AMD vs NVidia, the NVidia day-zero drivers are apparently going super-fucky on a lot of people, requiring a lot of downtuning and still low framerates. I played 8 hours straight last night on and AMD processor and video card and the only thing I saw that went awry was a minor animation glitch for an in-engine cutscene.
Everyone's blaming CDPR, but honestly I think a lot of it is probably the driver itself having an issue that was unforeseen, because we're all running the same core code, and every report I have seen on PC with video card models listed, it's a newer Nvidia card.
This does happen on day zero a lot of the time with big releases, I just wish people had a modicum of patience. It's a big launch with a lot of new technologies at play, it will be far better, hopefully in short order.