I keep seeing people mention that current high-end PC GPUs don't need more than X amount of ram and so there'll be no need for much more in next gen consoles.
As has been mentioned here many times, a console has to share that memory (and its bandwidth) between the CPU and GPU; and the console OS. The PS4 uses 2.5-3.0GB for the OS; up from ~70MB on the PS3. I can easily see the PS5 OS using 4-8GB.
Also, when PS4 came out the best spec GPUs were in the 3-6GB region, 8GB Single GPUs didn't come to PC for another year to a year and a half after that... and we're talking 290X's, Ti's and Titans.
An integral part of a new console generation is to move the goal posts and set a new baseline, you can't judge the required specs based off what PCs currently use.
I concede that the requirement for a jump in RAM isn't as high as it was before and that prices are no doubt going to represent a challenge, but 2x as the basis for a platform that needs to be a flagship system for 6-8yrs and have a lifespan of 10yrs just doesn't strike me as being practical; even taking into account advances in compression, smart memory controllers and flash caches.
I can't imagine a PS5 with 16GB RAM & 500-600GB/s Bandwidth in the years approaching 2030... Mid-gen refreshes could help a little but the games will ultimately be structured around and limited by the base console in everything but Resolution, FX & Framerate.
I think 24GB @ 768GB/s (Game) + 8GB @ ~40GB/s (OS) is the baseline and I hope for 32GB @ >920GB/s (Game/OS).
In regards to the CPU, I really see no reason to go for anything other than an 8 Core / 16 Thread Zen 2, the gains in die space for dropping multi-threading is negligible and the gain in die space for dropping to 4 or 6 cores won't gain you much in GPU power to make it worth losing 25-50% of your CPU cores..
The relative physical and thermal footprint of a 3.0-3.2GHz 8C/16T Zen 2 will be roughly the same as the Jaguar CPU in PS4. There's likely little to be gained by going for less or more, I think that's the sweet-spot.
I expect:
$399
APU with 8C/16T ZEN2 @ 3GHz & Navi/NG GPU @ ~12TF
24GB GDDR6 @ ~768GB/s (Game) + 8GB DDR4 @ ~40GB/s
1.5TB 5400RPM HDD + 32GB NAND Cache
I hope for:
$449
APU with 8C/16T ZEN2 @ 3.2GHz & Navi/NG GPU @ ~14TF
32GB HBM3 @ 0.9-1.4TB/s
2TB 7200RPM HDD + 64GB NAND Cache + HBCC Memory Controller
Sony are also likely to be the biggest potential customer for high capacity, high speed RAM chips, full stop. Compared to Consumer GPUs, Pro GPUs, Microsoft and all other areas; barring any major cock-ups and depending on the specific technology and densities used, they'll be ordering 2-16 chips per unit and are pretty much guaranteed to sell 80-120 million units over the platform lifespan. I wouldn't be surprised if they alone could shift a promising but problematic and expensive technology [like HBM] to a mainstream technology; benefiting all parties involved and the industry as a whole while getting a great deal. (GDRR6 is pretty much the end of GDDR imo, and HBM or something very similar will soon become a necessity).