PS will focus more on CPU this time around. Even with XB1X, they did everything they could to push Jaguar as much as possible, considering it may have to last 8 years or more due to their no more gens plan going forward. I would assume more money will be dedicated to the CPU, RAM, HDD/SSD, with less towards the GPU for PS5.
This makes me think PS5 will stick with 8, x86 cores, most likely Ryzen based, and also because PS4 has 8 cores, so dropping to 4 or 6 would seem like going backwards. 8 cores around 2020 won't seem like a big deal anyway.
I would assume the GPU ends up around 10TF. The XB1X can run some AAA at full 4k with 6TF, so 10TF would be more than enough for a base model, assuming PS5 Pro shows up at some point, and checkerboarding is still an option.
XB1X having 12GB of RAM leads me to believe PS5 will have a min of 16GB. This would probably require 4GB of dedicated separate OS RAM for future proofing, so 20GB total. A 20-24GB pool wouldn't be out of the question either.
As for storage they can't just stick with HDD due to load times, but how much solid state they can squeeze in the budget is really hard to say at this point in time, along with all the new storage tech that keeps popping up and the supply/pricing variations. With the system being fully 4k capable, 2TB of storage should be an absolute min.
If I were PS, I would guess XB "Two" wouldn't show up until 2021, so launching PS5 late 2020 would make sense. Make the system for around $500, and sell it for $499 late 2020. Then drop the price to $399 late 2021. This way if XB "Two" launches at $499, PS5 has a $100 price advantage just like Pro has. If XB tries to hit the magic $399 price point, it ends up the same price as PS5, so more than likely it's specs aren't much better either, so PS has little to worry about other than games.
PS5 using the success of the PS4 and getting an entire year lead makes the most sense to me. The only downside to this I could see, would be if XB decides to create a $500-$600 console, and sells it for around $399. PS really has no other option than to fight that with games or it's own subsidy at that point though, or launch a Pro model sooner than later.
While a traditional single console is the likely outcome, I also think it's possible to see a $399 PS5 and $599 Pro at launch. This way, XB "Two" at best could only end up on the cheaper end of the scale at $399 as well. Launching at $499 would not be good as PS5 would have a cheaper and more capable system surrounding it. Launching at $599 would make it much more niche like the XB1X is now, and would direct many XB customers towards the much cheaper XB1X at $299 at that time. A $299 XB1X isn't exactly good news for a $399 PS5 either, but if XB gamers prefer higher specs, PS5 would have that covered on both fronts.
The reason I can see this happening, is because I don't see PS4 Pro being able to play PS5 games, yet if the XB1X can play XB"Two" games, then PS would only have one console choice at $399, while XB would have two choices at $299 and $499. I could see this scenario being a bit of a problem for PS5 until the Pro released 2 or 3 years down the road. PS may have learned their PS3 lesson, but I think this would work considering they would have their affordable $399 version, so the $599 Pro model would be their 1/5th or possibly 2/5th sales over the gen again.
The other option is to launch the PS5 late 2019 with a two year head start, and follow up XB"Two" in 2021 with a stronger PS5 Pro in 2022.
