@Boerewors

Everything you say is about right. The PS4 has a weak link in that its CPU is underpowered. It's just not fast enough to process floods of tiny instructions in rapid succession and the fact that the RAM is GDDR5 does not help, because that adds a bit of latency as well when passing data to the CPU. CPU cache memory is too small to hold game code instructions permanently, so they are loaded into the GDDR5 RAM when the game boots up which has slow latency getting those instructions to the CPU when needed.

PS4 works best with games that are graphics heavy with lots of high res textures, complex lighting and lots of assets that get reused, because that makes good use of its powerful GPU. Games that require a lot of small vector calculations such as No Man's Sky, where everything is flat shaded vector artwork procedurally generated in rapid succession, puts excessive strain on the weak CPU.

Latency and speed are totally different, but equally important. It's best described using the internet as an example. Data speed is the speed the data travels. Latency is the short delay before the data starts traveling. As an extreme example, it does not matter if a 10GB download takes 1 second to start (latency), if it downloads in 10 minutes (speed). But in multiplayer gaming, a one second delay in sending the data of you shooting someone is just not going to work. Small instructions in rapid succession require low latency because they all add up very quickly.

The powerful GPU inside the PS4 and large capacity fast GDDR5 RAM are underused by No Man's Sky because there are no high res textures and no assets that get loaded and reused. Everything is procedurally generated fresh in real time where ever you go. The PS4 hardware is not well suited to that type of game.

AC Unity hit a CPU bottleneck as well by overloading the CPU with massive floods of AI, and all the AI streaming animations and physics. This then affects the CPU's ability to manage a steady frame rate because the powerful GPU was then left waiting for instructions to process. Another side effect of overloading the CPU is that it then generates controller latency, so that there is a delay in responding to the players controller instructions because the CPU is too busy or CPU bound (no spare resources). AC Unity suffers bad controller latency as a result, but it did use high quality textures and reused assets, so it did make use of a broad range of the PS4 hardware.

The PS4 runs into problems when a game is not designed well to make use of all the hardware equally. If the game produces excessive CPU activity, leaves the GPU idle and does not make use of the fast GDDR5 RAM, then the performance will suffer. The XB1 is the opposite because MS raised the CPU clock speed slightly and use low latency DDR3 RAM, so it performs a little better on the vector stuff, but performs poorly on the high res texture stuff because of its weak GPU and zero GDDR5 RAM. That is why the XB1 can only manage 900p on most games. A version of No Man's Sky on the XB1 may be able to push out 1080p, but it would be very tight.

No Man's Sky is possibly the worse game you could put on PS4 because it is not a good match. That is not No Man's Sky's fault. It is because Sony had to make the PS4 to a budget and chose to save money on the CPU side which was entirely valid at the time. Normally that is not a problem, but occasionally a game comes along that just spams the CPU.

I'm hoping Sony release the PS4 Elite they are considering. They can then fix the limitations in the PS4 standard edition. Three PS4 weakness's need to be addressed in the PS4 Elite.

1 - The CPU needs to be beefed up and run at a higher clock speed to cater for vector and physics intensive games.

2 - 4GB of low latency DDR3 RAM needs to be added to feed the CPU so the high latency fast speed GDDR5 RAM can just be used to feed the powerful GPU.

3 - A 4TB hard drive (2 x 2TB) should be added to store games because gamers are now avoiding buying games they want because they don't have the room for them without deleting their favourite games. A ticking time bomb for Sony that they need to address quickly.

The PS4 Elite and PS4 standard can exist side by side playing the same game disc because the architecture is scaleable. Games can be made to automatically sense the hardware and deliver the required optimisation that each PS4 version can handle.

Existing PS4 gamers will still be able to play the future games at the quality they have at present, so their investment is protected, but anyone that can afford to upgrade to a PS4 Elite will be rewarded by better performance.

In the short term Sony need to manufacture an optional hard drive expansion unit that clips onto the left side of the PS4 adding 4TB of RAM (2 x 2TB) that includes an empty slot for the existing internal hard drive to make it a simple hot swap installation with no data copying. That will keep the PS4 standard version running until the end of its lifespan without players needing to delete games.

There is an argument that a hard drive extension unit should be heavily subsidised by Sony because they gain financially with all the game sales it prevents them from loosing. Sony need to run the numbers and see if they loose more by not providing a subsidy with gamers not buying games, or provide a hardware subsidy and sell more games.