One thing a lot of tech savvy people have been saying is that the PS4 Pro's specs don't seem strong enough to put it in the proper league to run games very well at native 4K. Well, Digital Foundry finally put the hardware to the test and they explained why games like The Last of Us don't run at 60fps at all times on the PS4 Pro at a sub-4K resolution.
Digital Foundry did a breakdown of The Last of Us: Remastered running on the PS4 Pro recently, and blatantly explained that some resolutions and frame-rate combinations are still just too much for the PS4 Pro...
The resolution is running at 3200 x 1800p, which is sub-ultra HD and a few notches below true native 4K resolution, which is 3840 x 2160. According to Digital Foundry, The Last of Us: Remastered runs at 60fps at 1080p on the vanilla PS4, but at 1800p on the PS4 Pro the game cannot maintain 60fps and regularly dips down to 54fps, creating an inconsistency in frame display output.
On the upside, the PS4 Pro can run The Last of Us at native 4K if the graphics settings for the frame-rate are lowered to 30fps.
For a bit of perspective, native 4K renders at 8.2 megapixels per frame. The 3200 x 1800 resolution the PS4 Pro is using for The Last of Us only renders at 5.7 megapixels per frame. So in order to run an older game like The Last of Us from the PS3 at close to 60fps the PS4 Pro has to give up 2.5 million pixels. This means that if you're expecting any game that looks like or has better graphics than The Last Of Us, it won't be running on the PS4 Pro at a steady 60fps above 1800p, which is sub-4K.
What's interesting is that there is no fidelity difference in The Last of Us on PS4 to PS4 Pro. Mesh details, geometry, animations, sounds and texture buffering and filtering are identical between both systems, according to Digital Foundry. The only difference is in the resolution bump for the PS4 Pro.
Another interesting thing about it is that the PS4 Pro runs the game worse at 1800p when targeting a 60fps refresh than the standard PS4 runs the game at 1080p with a 60fps refresh. So technically, you could go with a PS4 Pro for the extra bump up in resolution but you'll be losing frames per second in some areas, even so much so that they found that the game dropped down to 50fps in some areas, which is detailed in the video comparison below.
The really bizarre thing is that the game has a hard-locked internal resolution of 1800p (even though it says 2160p in the options menu) so when you turn the graphics in the settings down to 1080p on the PS4 Pro, it still has the same frame-rate issues when running at native 1800p.
If this benchmark is anything to go by, the PS4 Pro is going to have a tough time on the market convincing people that it can play 4K games natively at frame rates above 30fps. Even with the extra GPU power, it's just not enough for 4K at a steady 60fps. There's obviously going to have to be concessions made somewhere, and in the case of The Last of Us: Remastered it looks like you'll get the most consistent performance at 4K at 30fps.