CPU: 6-16 Zen cores or it's successor/alternative.
GPU: 33.6 FP32 TF, 67.2 FP16 TF
Memory: 24-64GB
Release: 2020-2022
FP32 capabilities is roughly 18x more powerful than the PS4 and 8x more powerful than the PS4 Pro.
FP16 capabilities is roughly 36x more powerful than the PS4.
CPU: 4-8 Zen cores or it's successor/alternative.
GPU: 25 FP32 TF, 50 FP16 TF
Memory: 24-48GB
Release: 2019-2020
FP32 capabilities is roughly 13x more powerful than the PS4 and 6x more powerful than the PS4 Pro.
FP16 capabilities is roughly 27x more powerful than the PS4.
EDIT - 8:32AM 07/02/2017
I think I may be wrong about the Teraflops, the architectures they're going to be using in the next generation consoles may be significantly different than the current Polaris and previous GCN GPUs, so you may not be able to compare the Teraflops so well, or maybe you will? Such is the fun of speculation!
Revised Specs
CPU: 6-16 Zen/Zen+ cores or it's successor/alternative.
GPU: 25+ FP32 TF, 50+ FP16 TF
Memory: 24-64GB GDDR5X/GDDR6/HBM2+
Release: 2020-2022
GPUs are over 10x more powerful than the PS4 and over 6x more powerful than the PS4 Pro.
CPU: 4-8 Zen/Zen+ cores or it's successor/alternative.
GPU: 16+ FP32 TF, 32+ FP16 TF
Memory: 24-48GB GDDR5X/GDDR6/HBM2+
Release: 2019-2020
GPUs are over 8x more powerful than the PS4 and over 4x more powerful than the PS4 Pro.