Next gen consoleswill need the power not only for a generational leap in graphics, but also the ability to show off that graphical improvement at 120fps and the ultra high HD resolutions that is required for virtual reality systems. The PS4 had approximately ten times the GPU flops as the PS3 GPU. As we go up in graphics power, the law of diminishing returns kicks in so we will need at least 10 times the flops or even more for a similar gain in graphics. If the PS4 is 1.8 tflops, the PS5 gpu will need to be 18.0 tflops, minimum. Lets round that to 20 tflops. Some games today only run at around 30fps, so to increase that to a minimum of 60fps for VR (then hoping that some built in chip in the unit may add frames or something to smooth out judder) we need 40tflops. I would also add the extra power needed for two 1080p displays, but I'll keep it at 40tflops to stop from being crucified.
At a minimum, the PSV, to be a true generational leap with VR, needs 40tflops of processing power. This means that the GPU would need to be manufactured sub 10nm, probably even at 7nm or less. I also think the GPU will need to use more power than the PS4 GPU. Instead of a 100 watt budget for the console, maybe a 150 watt budget could be adopted.
Basically, we are talking about some serious GPU horsepower. But it is required if we want a graphics boost as visually apparent as the PS3-PS4 transition and high quality VR at the same time.
I don't see any way around this, unless Sony and Microsoft give up on a significant graphics bump and only allow for slightly better than today's quality games in VR.
I should also say that better bandwidth and other improvements other than flops could somewhat reduce the GPU flop total needed. But if we add a resolution boost to the 40 tflop figure, such bandwidth benefits are negated. Basically...
Good Graphics Leap - 20tflop GPU
Good Graphics Leap w/ high frame rate - 40 tflop GPU.
All of Above With Higher Resolution for VR - 50tflop? 60tflop?
Dedicated Hardware To Add Frames To Reduce Judder - Back down to 40 tflop?
My guess is the next generation of consoles.
2020 Launch
7nm 40tflop nVidia or AMD GPU
Integrated CPU on same chip
32gigs RAM
Totally VR Focused
Dedicated Hardware To Reduce GPU Burden