Taking The Last Guardian for a spin on both PlayStation 4 and PlayStation 4 Pro, Digital Foundry discovered that PS4 Pro owners running the game at 1080p will experience a smooth 30 frames-per-second, while regular PS4 owners and those running it at 4K will see frame-rate drops.
Starting with the standard PS4, Digital Foundry says it runs at native 1080p, but the frame-rate ranges from 20fps – 30fps, delivering the worst performance among all three options. On the plus side though, there aren’t any frame-pacing issues at 30fps.
Running on PS4 Pro at 4K resolution gets you a native 1890p image and a slightly higher frame-rate than PS4, but “performance can struggle in this mode in more taxing scenes.” At 1080p on PS4 Pro, you’ll get the same image quality as a standard PS4, and “PS4 Pro reallocates its resources in this 1080p mode by simply making it run at a much smoother frame-rate than is possible otherwise.” “From a performance perspective, the bottom line is this,” Digital Foundry adds. “The only option available to PlayStation gamers in getting a regularly smooth 30fps is to use PlayStation 4 Pro, running at 1080p.”

If you have a PS4 Pro, there aren’t any in-game video settings options in The Last Guardian, so you’ll have to change the resolution by going into the system’s settings, selecting Sound and Screen, and then selecting Video Output Settings.
As for any graphical differ...