While this is a great video, I am confused why the APU is being referred to as an SoC. It seems to contain just CPU+graphics, which AMD defines as "APU":
The AMD Accelerated Processing Unit (APU), formerly known as Fusion, is the marketing term for a series of 64-bit microprocessors from Advanced Micro Devices (AMD), designed to act as a central processing unit (CPU) and graphics processing unit (GPU) on a single die. APUs are general purpose processors that feature integrated graphics processors (IGPs).[0]
The memory modules on the PS5 are not built in, which seems to be a key factor to the definition of SoC:
A system on a chip (SoC) is an integrated circuit (also known as a "chip") that integrates all or most components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memory, input/output ports and secondary storage – all on a single substrate or microchip, the size of a coin.[1]
Memory modules? AFAIK Not a single SoC in wide use has the main memory
(of this size) on chip, sure the controllers might be and caches too, but not the system memory itself, memory is dense and typically requires large floor plans. I don't think the naming is as odd as it seems. There are likely very complex system components in that chip, not just a "CPU+GPU".
For example, the raspberry pi uses a broadcom SoC, the DDR memory is external, that doesn't stop them from still calling it one even though they might offload certain features (like how the PS5 has offloaded the disk controller).
The original Raspberry Pi had all of that on one chip, but it does look like the later models do not have it all in one, perhaps because the larger memory capacities cannot actually fit in a chip of that size. So it seems you are right.
Higher performance SOCs have caches and memory controllers integrated, but main memory and main non-volatile storage external so they can be varied at assembly for different SKUs.
The AMD Accelerated Processing Unit (APU), formerly known as Fusion, is the marketing term for a series of 64-bit microprocessors from Advanced Micro Devices (AMD), designed to act as a central processing unit (CPU) and graphics processing unit (GPU) on a single die. APUs are general purpose processors that feature integrated graphics processors (IGPs).[0]
The memory modules on the PS5 are not built in, which seems to be a key factor to the definition of SoC:
A system on a chip (SoC) is an integrated circuit (also known as a "chip") that integrates all or most components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memory, input/output ports and secondary storage – all on a single substrate or microchip, the size of a coin.[1]
[0] https://en.wikipedia.org/wiki/AMD_Accelerated_Processing_Uni...
[1] https://en.wikipedia.org/wiki/System_on_a_chip